diff mbox series

[FFmpeg-devel,v13,01/14] global: Prepare AVFrame for subtitle handling

Message ID MN2PR04MB5981F4CFFE09F9B678738AFFBAB59@MN2PR04MB5981.namprd04.prod.outlook.com
State New
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Series [FFmpeg-devel,v13,01/14] global: Prepare AVFrame for subtitle handling
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Context Check Description
andriy/make_x86 success Make finished
andriy/make_fate_x86 success Make fate finished
andriy/makex86 warning New warnings during build
andriy/make_ppc success Make finished
andriy/make_fate_ppc success Make fate finished
andriy/makeppc warning New warnings during build

Commit Message

Soft Works Oct. 11, 2021, 4:50 a.m. UTC
Root commit for adding subtitle filtering capabilities.
In detail:

- Add type (AVMediaType) field to AVFrame
  Replaces previous way of distinction which was based on checking
  width and height to determine whether a frame is audio or video
- Add subtitle fields to AVFrame
- Add new struct AVSubtitleArea, similar to AVSubtitleRect, but different
  allocation logic. Cannot and must not be used interchangeably, hence
  the new struct
- Move enum AVSubtitleType, AVSubtitle and AVSubtitleRect to avutil
- Add public-named members to enum AVSubtitleType (AV_SUBTITLE_FMT_)
- Add avcodec_decode_subtitle3 which takes subtitle frames,
  serving as compatibility shim to legacy subtitle decoding
- Add additional methods for conversion between old and new API

Signed-off-by: softworkz <softworkz@hotmail.com>
---
 libavcodec/avcodec.c       |  19 ---
 libavcodec/avcodec.h       |  75 ++----------
 libavcodec/decode.c        |  53 ++++++--
 libavcodec/pgssubdec.c     |   1 +
 libavcodec/utils.c         |  11 ++
 libavfilter/vf_subtitles.c |  50 ++++++--
 libavformat/utils.c        |   1 +
 libavutil/Makefile         |   2 +
 libavutil/frame.c          | 191 +++++++++++++++++++++++++----
 libavutil/frame.h          |  93 +++++++++++++-
 libavutil/subfmt.c         | 240 +++++++++++++++++++++++++++++++++++++
 libavutil/subfmt.h         | 185 ++++++++++++++++++++++++++++
 12 files changed, 796 insertions(+), 125 deletions(-)
 create mode 100644 libavutil/subfmt.c
 create mode 100644 libavutil/subfmt.h
diff mbox series

Patch

diff --git a/libavcodec/avcodec.c b/libavcodec/avcodec.c
index ff3d73e237..52ce345d49 100644
--- a/libavcodec/avcodec.c
+++ b/libavcodec/avcodec.c
@@ -422,25 +422,6 @@  void avcodec_flush_buffers(AVCodecContext *avctx)
         av_bsf_flush(avci->bsf);
 }
 
-void avsubtitle_free(AVSubtitle *sub)
-{
-    int i;
-
-    for (i = 0; i < sub->num_rects; i++) {
-        av_freep(&sub->rects[i]->data[0]);
-        av_freep(&sub->rects[i]->data[1]);
-        av_freep(&sub->rects[i]->data[2]);
-        av_freep(&sub->rects[i]->data[3]);
-        av_freep(&sub->rects[i]->text);
-        av_freep(&sub->rects[i]->ass);
-        av_freep(&sub->rects[i]);
-    }
-
-    av_freep(&sub->rects);
-
-    memset(sub, 0, sizeof(*sub));
-}
-
 av_cold int avcodec_close(AVCodecContext *avctx)
 {
     int i;
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 7ee8bc2b7c..0c5819b116 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -35,6 +35,7 @@ 
 #include "libavutil/frame.h"
 #include "libavutil/log.h"
 #include "libavutil/pixfmt.h"
+#include "libavutil/subfmt.h"
 #include "libavutil/rational.h"
 
 #include "codec.h"
@@ -1674,7 +1675,7 @@  typedef struct AVCodecContext {
 
     /**
      * Header containing style information for text subtitles.
-     * For SUBTITLE_ASS subtitle type, it should contain the whole ASS
+     * For AV_SUBTITLE_FMT_ASS subtitle type, it should contain the whole ASS
      * [Script Info] and [V4+ Styles] section, plus the [Events] line and
      * the Format line following. It shouldn't include any Dialogue line.
      * - encoding: Set/allocated/freed by user (before avcodec_open2())
@@ -2238,63 +2239,8 @@  typedef struct AVHWAccel {
  * @}
  */
 
-enum AVSubtitleType {
-    SUBTITLE_NONE,
-
-    SUBTITLE_BITMAP,                ///< A bitmap, pict will be set
-
-    /**
-     * Plain text, the text field must be set by the decoder and is
-     * authoritative. ass and pict fields may contain approximations.
-     */
-    SUBTITLE_TEXT,
-
-    /**
-     * Formatted text, the ass field must be set by the decoder and is
-     * authoritative. pict and text fields may contain approximations.
-     */
-    SUBTITLE_ASS,
-};
-
 #define AV_SUBTITLE_FLAG_FORCED 0x00000001
 
-typedef struct AVSubtitleRect {
-    int x;         ///< top left corner  of pict, undefined when pict is not set
-    int y;         ///< top left corner  of pict, undefined when pict is not set
-    int w;         ///< width            of pict, undefined when pict is not set
-    int h;         ///< height           of pict, undefined when pict is not set
-    int nb_colors; ///< number of colors in pict, undefined when pict is not set
-
-    /**
-     * data+linesize for the bitmap of this subtitle.
-     * Can be set for text/ass as well once they are rendered.
-     */
-    uint8_t *data[4];
-    int linesize[4];
-
-    enum AVSubtitleType type;
-
-    char *text;                     ///< 0 terminated plain UTF-8 text
-
-    /**
-     * 0 terminated ASS/SSA compatible event line.
-     * The presentation of this is unaffected by the other values in this
-     * struct.
-     */
-    char *ass;
-
-    int flags;
-} AVSubtitleRect;
-
-typedef struct AVSubtitle {
-    uint16_t format; /* 0 = graphics */
-    uint32_t start_display_time; /* relative to packet pts, in ms */
-    uint32_t end_display_time; /* relative to packet pts, in ms */
-    unsigned num_rects;
-    AVSubtitleRect **rects;
-    int64_t pts;    ///< Same as packet pts, in AV_TIME_BASE
-} AVSubtitle;
-
 /**
  * Return the LIBAVCODEC_VERSION_INT constant.
  */
@@ -2430,13 +2376,6 @@  int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **op
  */
 int avcodec_close(AVCodecContext *avctx);
 
-/**
- * Free all allocated data in the given subtitle struct.
- *
- * @param sub AVSubtitle to free.
- */
-void avsubtitle_free(AVSubtitle *sub);
-
 /**
  * @}
  */
@@ -2527,6 +2466,8 @@  enum AVChromaLocation avcodec_chroma_pos_to_enum(int xpos, int ypos);
  *                 must be freed with avsubtitle_free if *got_sub_ptr is set.
  * @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
  * @param[in] avpkt The input AVPacket containing the input buffer.
+ *
+ * @deprecated Use the new decode API (avcodec_send_packet, avcodec_receive_frame) instead.
  */
 int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
                             int *got_sub_ptr,
@@ -3125,6 +3066,14 @@  void avcodec_flush_buffers(AVCodecContext *avctx);
  */
 int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes);
 
+/**
+ * Return subtitle format from a codec descriptor
+ *
+ * @param codec_descriptor codec descriptor
+ * @return                 the subtitle type (e.g. bitmap, text)
+ */
+enum AVSubtitleType av_get_subtitle_format_from_codecdesc(const AVCodecDescriptor *codec_descriptor);
+
 /* memory */
 
 /**
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 294c040716..b2495f8578 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -577,6 +577,34 @@  static int decode_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
     return ret;
 }
 
+static int decode_subtitle2_priv(AVCodecContext *avctx, AVSubtitle *sub,
+                                 int *got_sub_ptr, const AVPacket *avpkt);
+
+static int decode_subtitle_shim(AVCodecContext *avctx, AVFrame *frame, const AVPacket *avpkt)
+{
+    int ret, got_sub_ptr = 0;
+    AVSubtitle subtitle = { 0 };
+
+    av_frame_unref(frame);
+
+    ret = decode_subtitle2_priv(avctx, &subtitle, &got_sub_ptr, avpkt);
+
+    if (ret >= 0 && got_sub_ptr) {
+        frame->type = AVMEDIA_TYPE_SUBTITLE;
+        frame->format = subtitle.format;
+        ret = av_frame_get_buffer2(frame, 0);
+        if (ret < 0)
+            return ret;
+        av_frame_put_subtitle(frame, &subtitle);
+
+        frame->pkt_dts = avpkt->dts;
+    }
+
+    avsubtitle_free(&subtitle);
+
+    return ret;
+}
+
 int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt)
 {
     AVCodecInternal *avci = avctx->internal;
@@ -591,6 +619,9 @@  int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacke
     if (avpkt && !avpkt->size && avpkt->data)
         return AVERROR(EINVAL);
 
+    if (avctx->codec_type == AVMEDIA_TYPE_SUBTITLE)
+        return decode_subtitle_shim(avctx, avci->buffer_frame, avpkt);
+
     av_packet_unref(avci->buffer_pkt);
     if (avpkt && (avpkt->data || avpkt->side_data_elems)) {
         ret = av_packet_ref(avci->buffer_pkt, avpkt);
@@ -652,7 +683,9 @@  int attribute_align_arg avcodec_receive_frame(AVCodecContext *avctx, AVFrame *fr
 
     if (avci->buffer_frame->buf[0]) {
         av_frame_move_ref(frame, avci->buffer_frame);
-    } else {
+    } else if (avctx->codec_type == AVMEDIA_TYPE_SUBTITLE)
+        return AVERROR(EAGAIN);
+    else {
         ret = decode_receive_frame_internal(avctx, frame);
         if (ret < 0)
             return ret;
@@ -724,7 +757,7 @@  static void get_subtitle_defaults(AVSubtitle *sub)
 
 #define UTF8_MAX_BYTES 4 /* 5 and 6 bytes sequences should not be used */
 static int recode_subtitle(AVCodecContext *avctx, AVPacket **outpkt,
-                           AVPacket *inpkt, AVPacket *buf_pkt)
+                           const AVPacket *inpkt, AVPacket *buf_pkt)
 {
 #if CONFIG_ICONV
     iconv_t cd = (iconv_t)-1;
@@ -803,9 +836,8 @@  static int utf8_check(const uint8_t *str)
     return 1;
 }
 
-int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
-                             int *got_sub_ptr,
-                             AVPacket *avpkt)
+static int decode_subtitle2_priv(AVCodecContext *avctx, AVSubtitle *sub,
+                             int *got_sub_ptr, const AVPacket *avpkt)
 {
     int ret = 0;
 
@@ -845,10 +877,7 @@  int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
                                                  avctx->pkt_timebase, ms);
         }
 
-        if (avctx->codec_descriptor->props & AV_CODEC_PROP_BITMAP_SUB)
-            sub->format = 0;
-        else if (avctx->codec_descriptor->props & AV_CODEC_PROP_TEXT_SUB)
-            sub->format = 1;
+        sub->format = av_get_subtitle_format_from_codecdesc(avctx->codec_descriptor);
 
         for (unsigned i = 0; i < sub->num_rects; i++) {
             if (avctx->sub_charenc_mode != FF_SUB_CHARENC_MODE_IGNORE &&
@@ -872,6 +901,12 @@  int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
     return ret;
 }
 
+int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
+                             int *got_sub_ptr, AVPacket *avpkt)
+{
+    return decode_subtitle2_priv(avctx, sub, got_sub_ptr, avpkt);
+}
+
 enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *avctx,
                                               const enum AVPixelFormat *fmt)
 {
diff --git a/libavcodec/pgssubdec.c b/libavcodec/pgssubdec.c
index 388639a110..5709058b1c 100644
--- a/libavcodec/pgssubdec.c
+++ b/libavcodec/pgssubdec.c
@@ -32,6 +32,7 @@ 
 #include "libavutil/colorspace.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
+#include "libavutil/subfmt.h"
 
 #define RGBA(r,g,b,a) (((unsigned)(a) << 24) | ((r) << 16) | ((g) << 8) | (b))
 #define MAX_EPOCH_PALETTES 8   // Max 8 allowed per PGS epoch
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index b4076d94f2..e1d667371a 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -823,6 +823,17 @@  int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes)
     return FFMAX(0, duration);
 }
 
+enum AVSubtitleType av_get_subtitle_format_from_codecdesc(const AVCodecDescriptor *codec_descriptor)
+{
+    if(codec_descriptor->props & AV_CODEC_PROP_BITMAP_SUB)
+        return AV_SUBTITLE_FMT_BITMAP;
+
+    if(codec_descriptor->props & AV_CODEC_PROP_TEXT_SUB)
+        return AV_SUBTITLE_FMT_ASS;
+
+    return AV_SUBTITLE_FMT_UNKNOWN;
+}
+
 int av_get_audio_frame_duration2(AVCodecParameters *par, int frame_bytes)
 {
     int duration = get_audio_frame_duration(par->codec_id, par->sample_rate,
diff --git a/libavfilter/vf_subtitles.c b/libavfilter/vf_subtitles.c
index 377160c72b..6b54cf669b 100644
--- a/libavfilter/vf_subtitles.c
+++ b/libavfilter/vf_subtitles.c
@@ -35,14 +35,12 @@ 
 # include "libavformat/avformat.h"
 #endif
 #include "libavutil/avstring.h"
-#include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "drawutils.h"
 #include "avfilter.h"
 #include "internal.h"
 #include "formats.h"
-#include "video.h"
 
 typedef struct AssContext {
     const AVClass *class;
@@ -292,6 +290,29 @@  static int attachment_is_font(AVStream * st)
     return 0;
 }
 
+static int decode(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *pkt)
+{
+    int ret;
+
+    *got_frame = 0;
+
+    if (pkt) {
+        ret = avcodec_send_packet(avctx, pkt);
+        // In particular, we don't expect AVERROR(EAGAIN), because we read all
+        // decoded frames with avcodec_receive_frame() until done.
+        if (ret < 0 && ret != AVERROR_EOF)
+            return ret;
+    }
+
+    ret = avcodec_receive_frame(avctx, frame);
+    if (ret < 0 && ret != AVERROR(EAGAIN))
+        return ret;
+    if (ret >= 0)
+        *got_frame = 1;
+
+    return 0;
+}
+
 AVFILTER_DEFINE_CLASS(subtitles);
 
 static av_cold int init_subtitles(AVFilterContext *ctx)
@@ -306,6 +327,7 @@  static av_cold int init_subtitles(AVFilterContext *ctx)
     AVStream *st;
     AVPacket pkt;
     AssContext *ass = ctx->priv;
+    enum AVSubtitleType subtitle_format;
 
     /* Init libass */
     ret = init(ctx);
@@ -386,13 +408,17 @@  static av_cold int init_subtitles(AVFilterContext *ctx)
         ret = AVERROR_DECODER_NOT_FOUND;
         goto end;
     }
+
     dec_desc = avcodec_descriptor_get(st->codecpar->codec_id);
-    if (dec_desc && !(dec_desc->props & AV_CODEC_PROP_TEXT_SUB)) {
+    subtitle_format = av_get_subtitle_format_from_codecdesc(dec_desc);
+
+    if (subtitle_format != AV_SUBTITLE_FMT_ASS) {
         av_log(ctx, AV_LOG_ERROR,
-               "Only text based subtitles are currently supported\n");
-        ret = AVERROR_PATCHWELCOME;
+               "Only text based subtitles are supported by this filter\n");
+        ret = AVERROR_INVALIDDATA;
         goto end;
     }
+
     if (ass->charenc)
         av_dict_set(&codec_opts, "sub_charenc", ass->charenc, 0);
 
@@ -448,18 +474,18 @@  static av_cold int init_subtitles(AVFilterContext *ctx)
                                   dec_ctx->subtitle_header_size);
     while (av_read_frame(fmt, &pkt) >= 0) {
         int i, got_subtitle;
-        AVSubtitle sub = {0};
+        AVFrame *sub = av_frame_alloc();
 
         if (pkt.stream_index == sid) {
-            ret = avcodec_decode_subtitle2(dec_ctx, &sub, &got_subtitle, &pkt);
+            ret = decode(dec_ctx, sub, &got_subtitle, &pkt);
             if (ret < 0) {
                 av_log(ctx, AV_LOG_WARNING, "Error decoding: %s (ignored)\n",
                        av_err2str(ret));
             } else if (got_subtitle) {
-                const int64_t start_time = av_rescale_q(sub.pts, AV_TIME_BASE_Q, av_make_q(1, 1000));
-                const int64_t duration   = sub.end_display_time;
-                for (i = 0; i < sub.num_rects; i++) {
-                    char *ass_line = sub.rects[i]->ass;
+                const int64_t start_time = av_rescale_q(sub->subtitle_pts, AV_TIME_BASE_Q, av_make_q(1, 1000));
+                const int64_t duration   = sub->subtitle_end_time;
+                for (i = 0; i < sub->num_subtitle_areas; i++) {
+                    char *ass_line = sub->subtitle_areas[i]->ass;
                     if (!ass_line)
                         break;
                     ass_process_chunk(ass->track, ass_line, strlen(ass_line),
@@ -468,7 +494,7 @@  static av_cold int init_subtitles(AVFilterContext *ctx)
             }
         }
         av_packet_unref(&pkt);
-        avsubtitle_free(&sub);
+        av_frame_free(&sub);
     }
 
 end:
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 509c0ecdce..f1ec4c4c2f 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -31,6 +31,7 @@ 
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/pixfmt.h"
+#include "libavutil/subfmt.h"
 #include "libavutil/thread.h"
 #include "libavutil/time.h"
 
diff --git a/libavutil/Makefile b/libavutil/Makefile
index 410ac636f7..04e1101bf3 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -74,6 +74,7 @@  HEADERS = adler32.h                                                     \
           sha512.h                                                      \
           spherical.h                                                   \
           stereo3d.h                                                    \
+          subfmt.h                                                      \
           threadmessage.h                                               \
           time.h                                                        \
           timecode.h                                                    \
@@ -159,6 +160,7 @@  OBJS = adler32.o                                                        \
        slicethread.o                                                    \
        spherical.o                                                      \
        stereo3d.o                                                       \
+       subfmt.o                                                         \
        threadmessage.o                                                  \
        time.o                                                           \
        timecode.o                                                       \
diff --git a/libavutil/frame.c b/libavutil/frame.c
index 2617cda2b5..53c5b018c2 100644
--- a/libavutil/frame.c
+++ b/libavutil/frame.c
@@ -26,6 +26,7 @@ 
 #include "imgutils.h"
 #include "mem.h"
 #include "samplefmt.h"
+#include "subfmt.h"
 #include "hwcontext.h"
 
 #define CHECK_CHANNELS_CONSISTENCY(frame) \
@@ -50,6 +51,9 @@  const char *av_get_colorspace_name(enum AVColorSpace val)
     return name[val];
 }
 #endif
+
+static int frame_copy_subtitles(AVFrame *dst, const AVFrame *src, int copy_data);
+
 static void get_frame_defaults(AVFrame *frame)
 {
     if (frame->extended_data != frame->data)
@@ -72,7 +76,12 @@  static void get_frame_defaults(AVFrame *frame)
     frame->colorspace          = AVCOL_SPC_UNSPECIFIED;
     frame->color_range         = AVCOL_RANGE_UNSPECIFIED;
     frame->chroma_location     = AVCHROMA_LOC_UNSPECIFIED;
-    frame->flags               = 0;
+    frame->subtitle_start_time = 0;
+    frame->subtitle_end_time   = 0;
+    frame->num_subtitle_areas  = 0;
+    frame->subtitle_areas      = NULL;
+    frame->subtitle_pts        = 0;
+    frame->subtitle_header     = NULL;
 }
 
 static void free_side_data(AVFrameSideData **ptr_sd)
@@ -243,23 +252,52 @@  static int get_audio_buffer(AVFrame *frame, int align)
 
 }
 
+static int get_subtitle_buffer(AVFrame *frame)
+{
+    // Buffers in AVFrame->buf[] are not used in case of subtitle frames.
+    // To accomodate with existing code, checking ->buf[0] to determine
+    // whether a frame is ref-counted or has data, we're adding a 1-byte
+    // buffer here, which marks the subtitle frame to contain data.
+    frame->buf[0] = av_buffer_alloc(1);
+    if (!frame->buf[0]) {
+        av_frame_unref(frame);
+        return AVERROR(ENOMEM);
+    }
+    return 0;
+}
+
 int av_frame_get_buffer(AVFrame *frame, int align)
+{
+    if (frame->width > 0 && frame->height > 0)
+        frame->type = AVMEDIA_TYPE_VIDEO;
+    else if (frame->nb_samples > 0 && (frame->channel_layout || frame->channels > 0))
+        frame->type = AVMEDIA_TYPE_AUDIO;
+
+    return av_frame_get_buffer2(frame, align);
+}
+
+int av_frame_get_buffer2(AVFrame *frame, int align)
 {
     if (frame->format < 0)
         return AVERROR(EINVAL);
 
-    if (frame->width > 0 && frame->height > 0)
+    switch(frame->type) {
+    case AVMEDIA_TYPE_VIDEO:
         return get_video_buffer(frame, align);
-    else if (frame->nb_samples > 0 && (frame->channel_layout || frame->channels > 0))
+    case AVMEDIA_TYPE_AUDIO:
         return get_audio_buffer(frame, align);
-
-    return AVERROR(EINVAL);
+    case AVMEDIA_TYPE_SUBTITLE:
+        return get_subtitle_buffer(frame);
+    default:
+        return AVERROR(EINVAL);
+    }
 }
 
 static int frame_copy_props(AVFrame *dst, const AVFrame *src, int force_copy)
 {
     int ret, i;
 
+    dst->type                   = src->type;
     dst->key_frame              = src->key_frame;
     dst->pict_type              = src->pict_type;
     dst->sample_aspect_ratio    = src->sample_aspect_ratio;
@@ -290,6 +328,12 @@  static int frame_copy_props(AVFrame *dst, const AVFrame *src, int force_copy)
     dst->colorspace             = src->colorspace;
     dst->color_range            = src->color_range;
     dst->chroma_location        = src->chroma_location;
+    dst->subtitle_start_time    = src->subtitle_start_time;
+    dst->subtitle_end_time      = src->subtitle_end_time;
+    dst->subtitle_pts           = src->subtitle_pts;
+
+    if ((ret = av_buffer_replace(&dst->subtitle_header, src->subtitle_header)) < 0)
+        return ret;
 
     av_dict_copy(&dst->metadata, src->metadata, 0);
 
@@ -331,6 +375,7 @@  int av_frame_ref(AVFrame *dst, const AVFrame *src)
     av_assert1(dst->width == 0 && dst->height == 0);
     av_assert1(dst->channels == 0);
 
+    dst->type           = src->type;
     dst->format         = src->format;
     dst->width          = src->width;
     dst->height         = src->height;
@@ -344,7 +389,7 @@  int av_frame_ref(AVFrame *dst, const AVFrame *src)
 
     /* duplicate the frame data if it's not refcounted */
     if (!src->buf[0]) {
-        ret = av_frame_get_buffer(dst, 0);
+        ret = av_frame_get_buffer2(dst, 0);
         if (ret < 0)
             goto fail;
 
@@ -366,6 +411,10 @@  int av_frame_ref(AVFrame *dst, const AVFrame *src)
         }
     }
 
+    /* copy subtitle areas */
+    if (src->type == AVMEDIA_TYPE_SUBTITLE)
+        frame_copy_subtitles(dst, src, 0);
+
     if (src->extended_buf) {
         dst->extended_buf = av_calloc(src->nb_extended_buf,
                                       sizeof(*dst->extended_buf));
@@ -436,7 +485,7 @@  AVFrame *av_frame_clone(const AVFrame *src)
 
 void av_frame_unref(AVFrame *frame)
 {
-    int i;
+    unsigned i, n;
 
     if (!frame)
         return;
@@ -455,6 +504,21 @@  void av_frame_unref(AVFrame *frame)
     av_buffer_unref(&frame->opaque_ref);
     av_buffer_unref(&frame->private_ref);
 
+    av_buffer_unref(&frame->subtitle_header);
+
+    for (i = 0; i < frame->num_subtitle_areas; i++) {
+        AVSubtitleArea *area = frame->subtitle_areas[i];
+
+        for (n = 0; n < FF_ARRAY_ELEMS(area->buf); n++)
+            av_buffer_unref(&area->buf[n]);
+
+        av_freep(&area->text);
+        av_freep(&area->ass);
+        av_free(area);
+    }
+
+    av_freep(&frame->subtitle_areas);
+
     get_frame_defaults(frame);
 }
 
@@ -472,7 +536,8 @@  void av_frame_move_ref(AVFrame *dst, AVFrame *src)
 
 int av_frame_is_writable(AVFrame *frame)
 {
-    int i, ret = 1;
+    AVSubtitleArea *area;
+    unsigned i, n, ret = 1;
 
     /* assume non-refcounted frames are not writable */
     if (!frame->buf[0])
@@ -484,6 +549,15 @@  int av_frame_is_writable(AVFrame *frame)
     for (i = 0; i < frame->nb_extended_buf; i++)
         ret &= !!av_buffer_is_writable(frame->extended_buf[i]);
 
+    for (i = 0; i < frame->num_subtitle_areas; i++) {
+        area = frame->subtitle_areas[i];
+        if (area) {
+            for (n = 0; n < FF_ARRAY_ELEMS(area->buf); n++)
+                if (area->buf[n])
+                    ret &= !!av_buffer_is_writable(area->buf[n]);
+            }
+    }
+
     return ret;
 }
 
@@ -499,6 +573,7 @@  int av_frame_make_writable(AVFrame *frame)
         return 0;
 
     memset(&tmp, 0, sizeof(tmp));
+    tmp.type           = frame->type;
     tmp.format         = frame->format;
     tmp.width          = frame->width;
     tmp.height         = frame->height;
@@ -509,7 +584,7 @@  int av_frame_make_writable(AVFrame *frame)
     if (frame->hw_frames_ctx)
         ret = av_hwframe_get_buffer(frame->hw_frames_ctx, &tmp, 0);
     else
-        ret = av_frame_get_buffer(&tmp, 0);
+        ret = av_frame_get_buffer2(&tmp, 0);
     if (ret < 0)
         return ret;
 
@@ -544,14 +619,22 @@  AVBufferRef *av_frame_get_plane_buffer(AVFrame *frame, int plane)
     uint8_t *data;
     int planes, i;
 
-    if (frame->nb_samples) {
-        int channels = frame->channels;
-        if (!channels)
-            return NULL;
-        CHECK_CHANNELS_CONSISTENCY(frame);
-        planes = av_sample_fmt_is_planar(frame->format) ? channels : 1;
-    } else
+    switch(frame->type) {
+    case AVMEDIA_TYPE_VIDEO:
         planes = 4;
+        break;
+    case AVMEDIA_TYPE_AUDIO:
+        {
+            int channels = frame->channels;
+            if (!channels)
+                return NULL;
+            CHECK_CHANNELS_CONSISTENCY(frame);
+            planes = av_sample_fmt_is_planar(frame->format) ? channels : 1;
+            break;
+        }
+    default:
+        return NULL;
+    }
 
     if (plane < 0 || plane >= planes || !frame->extended_data[plane])
         return NULL;
@@ -675,17 +758,39 @@  static int frame_copy_audio(AVFrame *dst, const AVFrame *src)
     return 0;
 }
 
+static int frame_copy_subtitles(AVFrame *dst, const AVFrame *src, int copy_data)
+{
+    dst->format = src->format;
+
+    dst->num_subtitle_areas = src->num_subtitle_areas;
+
+    if (src->num_subtitle_areas) {
+        dst->subtitle_areas = av_malloc_array(src->num_subtitle_areas, sizeof(AVSubtitleArea *));
+
+        for (unsigned i = 0; i < src->num_subtitle_areas; i++) {
+            dst->subtitle_areas[i] = av_mallocz(sizeof(AVSubtitleArea));
+            av_subtitle_area2area(dst->subtitle_areas[i], src->subtitle_areas[i], copy_data);
+        }
+    }
+
+    return 0;
+}
+
 int av_frame_copy(AVFrame *dst, const AVFrame *src)
 {
     if (dst->format != src->format || dst->format < 0)
         return AVERROR(EINVAL);
 
-    if (dst->width > 0 && dst->height > 0)
+    switch(dst->type) {
+    case AVMEDIA_TYPE_VIDEO:
         return frame_copy_video(dst, src);
-    else if (dst->nb_samples > 0 && dst->channels > 0)
+    case AVMEDIA_TYPE_AUDIO:
         return frame_copy_audio(dst, src);
-
-    return AVERROR(EINVAL);
+    case AVMEDIA_TYPE_SUBTITLE:
+        return frame_copy_subtitles(dst, src, 1);
+    default:
+        return AVERROR(EINVAL);
+    }
 }
 
 void av_frame_remove_side_data(AVFrame *frame, enum AVFrameSideDataType type)
@@ -831,3 +936,49 @@  int av_frame_apply_cropping(AVFrame *frame, int flags)
 
     return 0;
 }
+
+/**
+ * Copies subtitle data from AVSubtitle (deprecated) to AVFrame
+ *
+ * @note This is a compatibility method for conversion to the legacy API
+ */
+void av_frame_put_subtitle(AVFrame *frame, AVSubtitle *sub)
+{
+    frame->format              = sub->format;
+    frame->subtitle_start_time = sub->start_display_time;
+    frame->subtitle_end_time   = sub->end_display_time;
+    frame->subtitle_pts        = sub->pts;
+    frame->num_subtitle_areas  = sub->num_rects;
+
+    if (sub->num_rects) {
+        frame->subtitle_areas = av_malloc_array(sub->num_rects, sizeof(AVSubtitleArea *));
+
+        for (unsigned i = 0; i < sub->num_rects; i++) {
+            frame->subtitle_areas[i] = av_mallocz(sizeof(AVSubtitleArea));
+            av_subtitle_rect2area(frame->subtitle_areas[i], sub->rects[i]);
+        }
+    }
+}
+
+/**
+ * Copies subtitle data from AVFrame to AVSubtitle (deprecated)
+ *
+ * @note This is a compatibility method for conversion to the legacy API
+ */
+void av_frame_get_subtitle(AVSubtitle *sub, AVFrame *frame)
+{
+    sub->start_display_time = frame->subtitle_start_time;
+    sub->end_display_time   = frame->subtitle_end_time;
+    sub->pts                = frame->subtitle_pts;
+    sub->num_rects          = frame->num_subtitle_areas;
+
+    if (frame->num_subtitle_areas) {
+        sub->rects = av_malloc_array(frame->num_subtitle_areas, sizeof(AVSubtitle *));
+
+        for (unsigned i = 0; i < frame->num_subtitle_areas; i++) {
+            sub->rects[i] = av_mallocz(sizeof(AVSubtitleRect));
+            av_subtitle_area2rect(sub->rects[i], frame->subtitle_areas[i]);
+        }
+    }
+}
+
diff --git a/libavutil/frame.h b/libavutil/frame.h
index ff2540a20f..21122819b1 100644
--- a/libavutil/frame.h
+++ b/libavutil/frame.h
@@ -34,6 +34,7 @@ 
 #include "rational.h"
 #include "samplefmt.h"
 #include "pixfmt.h"
+#include "subfmt.h"
 #include "version.h"
 
 
@@ -271,7 +272,7 @@  typedef struct AVRegionOfInterest {
 } AVRegionOfInterest;
 
 /**
- * This structure describes decoded (raw) audio or video data.
+ * This structure describes decoded (raw) audio, video or subtitle data.
  *
  * AVFrame must be allocated using av_frame_alloc(). Note that this only
  * allocates the AVFrame itself, the buffers for the data must be managed
@@ -302,6 +303,13 @@  typedef struct AVRegionOfInterest {
  */
 typedef struct AVFrame {
 #define AV_NUM_DATA_POINTERS 8
+    /**
+     * Media type of the frame (audio, video, subtitles..)
+     *
+     * See AVMEDIA_TYPE_xxx
+     */
+    enum AVMediaType type;
+
     /**
      * pointer to the picture/channel planes.
      * This might be different from the first allocated byte
@@ -371,7 +379,7 @@  typedef struct AVFrame {
     /**
      * format of the frame, -1 if unknown or unset
      * Values correspond to enum AVPixelFormat for video frames,
-     * enum AVSampleFormat for audio)
+     * enum AVSampleFormat for audio, AVSubtitleType for subtitles)
      */
     int format;
 
@@ -462,6 +470,39 @@  typedef struct AVFrame {
      */
     uint64_t channel_layout;
 
+    /**
+     * Display start time, relative to packet pts, in ms.
+     */
+    uint32_t subtitle_start_time;
+
+    /**
+     * Display end time, relative to packet pts, in ms.
+     */
+    uint32_t subtitle_end_time;
+
+    /**
+     * Number of items in the @ref subtitle_areas array.
+     */
+    unsigned num_subtitle_areas;
+
+    /**
+     * Array of subtitle areas, may be empty.
+     */
+    AVSubtitleArea **subtitle_areas;
+
+    /**
+     * Usually the same as packet pts, in AV_TIME_BASE.
+     *
+     * @deprecated This is kept for compatibility reasons and corresponds to
+     * AVSubtitle->pts. Might be removed in the future.
+     */
+    int64_t subtitle_pts;
+
+    /**
+     * Header containing style information for text subtitles.
+     */
+    AVBufferRef *subtitle_header;
+
     /**
      * AVBuffer references backing the data for this frame. If all elements of
      * this array are NULL, then this frame is not reference counted. This array
@@ -721,6 +762,8 @@  void av_frame_move_ref(AVFrame *dst, AVFrame *src);
 /**
  * Allocate new buffer(s) for audio or video data.
  *
+ * Note: For subtitle data, use av_frame_get_buffer2
+ *
  * The following fields must be set on frame before calling this function:
  * - format (pixel format for video, sample format for audio)
  * - width and height for video
@@ -740,9 +783,39 @@  void av_frame_move_ref(AVFrame *dst, AVFrame *src);
  *              recommended to pass 0 here unless you know what you are doing.
  *
  * @return 0 on success, a negative AVERROR on error.
+ *
+ * @deprecated Use @ref av_frame_get_buffer2 instead and set @ref AVFrame.type
+ * before calling.
  */
+attribute_deprecated
 int av_frame_get_buffer(AVFrame *frame, int align);
 
+/**
+ * Allocate new buffer(s) for audio, video or subtitle data.
+ *
+ * The following fields must be set on frame before calling this function:
+ * - format (pixel format for video, sample format for audio)
+ * - width and height for video
+ * - nb_samples and channel_layout for audio
+ * - type (AVMediaType)
+ *
+ * This function will fill AVFrame.data and AVFrame.buf arrays and, if
+ * necessary, allocate and fill AVFrame.extended_data and AVFrame.extended_buf.
+ * For planar formats, one buffer will be allocated for each plane.
+ *
+ * @warning: if frame already has been allocated, calling this function will
+ *           leak memory. In addition, undefined behavior can occur in certain
+ *           cases.
+ *
+ * @param frame frame in which to store the new buffers.
+ * @param align Required buffer size alignment. If equal to 0, alignment will be
+ *              chosen automatically for the current CPU. It is highly
+ *              recommended to pass 0 here unless you know what you are doing.
+ *
+ * @return 0 on success, a negative AVERROR on error.
+ */
+int av_frame_get_buffer2(AVFrame *frame, int align);
+
 /**
  * Check if the frame data is writable.
  *
@@ -844,6 +917,22 @@  AVFrameSideData *av_frame_get_side_data(const AVFrame *frame,
  */
 void av_frame_remove_side_data(AVFrame *frame, enum AVFrameSideDataType type);
 
+/**
+ * Copies subtitle data from AVSubtitle to AVFrame.
+ *
+ * @deprecated This is a compatibility method for interoperability with
+ * the legacy subtitle API.
+ */
+void av_frame_put_subtitle(AVFrame *frame, AVSubtitle *sub);
+
+/**
+ * Copies subtitle data from AVFrame to AVSubtitle.
+ *
+ * @deprecated This is a compatibility method for interoperability with
+ * the legacy subtitle API.
+ */
+void av_frame_get_subtitle(AVSubtitle *sub, AVFrame *frame);
+
 
 /**
  * Flags for frame cropping.
diff --git a/libavutil/subfmt.c b/libavutil/subfmt.c
new file mode 100644
index 0000000000..24fbeffacd
--- /dev/null
+++ b/libavutil/subfmt.c
@@ -0,0 +1,240 @@ 
+/*
+ * Copyright (c) 2021 softworkz
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <string.h>
+#include "common.h"
+#include "subfmt.h"
+
+typedef struct SubtitleFmtInfo {
+    enum AVSubtitleType fmt;
+    const char* name;
+} SubtitleFmtInfo;
+
+static SubtitleFmtInfo sub_fmt_info[AV_SUBTITLE_FMT_NB] = {
+    {.fmt = AV_SUBTITLE_FMT_UNKNOWN, .name = "Unknown subtitle format", },
+    {.fmt = AV_SUBTITLE_FMT_BITMAP,  .name = "Graphical subtitles",     },
+    {.fmt = AV_SUBTITLE_FMT_TEXT,    .name = "Text subtitles (plain)",  },
+    {.fmt = AV_SUBTITLE_FMT_ASS,     .name = "Text subtitles (ass)",    },
+};
+
+const char *av_get_subtitle_fmt_name(enum AVSubtitleType sub_fmt)
+{
+    if (sub_fmt < 0 || sub_fmt >= AV_SUBTITLE_FMT_NB)
+        return NULL;
+    return sub_fmt_info[sub_fmt].name;
+}
+
+enum AVSubtitleType av_get_subtitle_fmt(const char *name)
+{
+    for (int i = 0; i < AV_SUBTITLE_FMT_NB; i++)
+        if (!strcmp(sub_fmt_info[i].name, name))
+            return i;
+    return AV_SUBTITLE_FMT_NONE;
+}
+
+int av_subtitle_area2rect(AVSubtitleRect *dst, const AVSubtitleArea *src)
+{
+    dst->x         =  src->x;        
+    dst->y         =  src->y;        
+    dst->w         =  src->w;        
+    dst->h         =  src->h;        
+    dst->nb_colors =  src->nb_colors;
+    dst->type      =  src->type;                     
+
+    switch (dst->type) {
+    case AV_SUBTITLE_FMT_BITMAP:
+
+        if (src->h > 0 && src->w > 0 && src->buf[0]) {
+            uint32_t *pal;
+            AVBufferRef *buf = src->buf[0];
+            dst->data[0] = av_mallocz(buf->size);
+            memcpy(dst->data[0], buf->data, buf->size);
+            dst->linesize[0] = src->linesize[0];
+
+            dst->data[1] = av_mallocz(256 * 4);
+            pal = (uint32_t *)dst->data[1];
+
+            for (unsigned i = 0; i < 256; i++) {
+                pal[i] = src->pal[i];
+            }
+        }
+
+        break;
+    case AV_SUBTITLE_FMT_TEXT:
+
+        if (src->text)
+            dst->text = av_strdup(src->text);
+        else
+            dst->text = av_strdup("");
+
+        if (!dst->text)
+            return AVERROR(ENOMEM);
+
+        break;
+    case AV_SUBTITLE_FMT_ASS:
+
+        if (src->ass)
+            dst->ass = av_strdup(src->ass);
+        else
+            dst->ass = av_strdup("");
+
+        if (!dst->ass)
+            return AVERROR(ENOMEM);
+
+        break;
+    default:
+
+        av_log(NULL, AV_LOG_ERROR, "Subtitle rect has invalid format: %d", dst->type);
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+int av_subtitle_rect2area(AVSubtitleArea *dst, const AVSubtitleRect *src)
+{
+    dst->x         =  src->x;        
+    dst->y         =  src->y;        
+    dst->w         =  src->w;        
+    dst->h         =  src->h;        
+    dst->nb_colors =  src->nb_colors;
+    dst->type      =  src->type;                     
+
+    switch (dst->type) {
+    case AV_SUBTITLE_FMT_BITMAP:
+
+        if (src->h > 0 && src->w > 0 && src->data[0]) {
+            AVBufferRef *buf = av_buffer_allocz(src->h * src->linesize[0]);
+            memcpy(buf->data, src->data[0], buf->size);
+
+            dst->buf[0] = buf;
+            dst->linesize[0] = src->linesize[0];
+        }
+
+        if (src->data[1]) {
+            uint32_t *pal = (uint32_t *)src->data[1];
+
+            for (unsigned i = 0; i < 256; i++) {
+                dst->pal[i] = pal[i];
+            }
+        }
+
+        break;
+    case AV_SUBTITLE_FMT_TEXT:
+
+        if (src->text) {
+            dst->text = av_strdup(src->text);
+            if (!dst->text)
+                return AVERROR(ENOMEM);
+        }
+
+        break;
+    case AV_SUBTITLE_FMT_ASS:
+
+        if (src->ass) {
+            dst->ass = av_strdup(src->ass);
+            if (!dst->ass)
+                return AVERROR(ENOMEM);
+        }
+
+        break;
+    default:
+
+        av_log(NULL, AV_LOG_ERROR, "Subtitle area has invalid format: %d", dst->type);
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+int av_subtitle_area2area(AVSubtitleArea *dst, const AVSubtitleArea *src, int copy_data)
+{
+    dst->x         =  src->x;        
+    dst->y         =  src->y;        
+    dst->w         =  src->w;        
+    dst->h         =  src->h;        
+    dst->nb_colors =  src->nb_colors;
+    dst->type      =  src->type;                     
+
+    switch (dst->type) {
+    case AV_SUBTITLE_FMT_BITMAP:
+
+        if (src->h > 0 && src->w > 0 && src->buf[0]) {
+            dst->buf[0] = av_buffer_ref(src->buf[0]);
+            if (!dst->buf[0])
+                return AVERROR(ENOMEM);
+
+            if (copy_data) {
+                const int ret = av_buffer_make_writable(&dst->buf[0]);
+                if (ret < 0)
+                    return ret;
+            }
+
+            dst->linesize[0] = src->linesize[0];
+        }
+
+        for (unsigned i = 0; i < 256; i++)
+            dst->pal[i] = src->pal[i];
+
+        break;
+    case AV_SUBTITLE_FMT_TEXT:
+
+        if (src->text) {
+            dst->text = av_strdup(src->text);
+            if (!dst->text)
+                return AVERROR(ENOMEM);
+        }
+
+        break;
+    case AV_SUBTITLE_FMT_ASS:
+
+        if (src->ass) {
+            dst->ass = av_strdup(src->ass);
+            if (!dst->ass)
+                return AVERROR(ENOMEM);
+        }
+
+        break;
+    default:
+
+        av_log(NULL, AV_LOG_ERROR, "Subtitle area has invalid format: %d", dst->type);
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+void avsubtitle_free(AVSubtitle *sub)
+{
+    for (unsigned i = 0; i < sub->num_rects; i++) {
+        av_freep(&sub->rects[i]->data[0]);
+        av_freep(&sub->rects[i]->data[1]);
+        av_freep(&sub->rects[i]->data[2]);
+        av_freep(&sub->rects[i]->data[3]);
+        av_freep(&sub->rects[i]->text);
+        av_freep(&sub->rects[i]->ass);
+        av_freep(&sub->rects[i]);
+    }
+
+    av_freep(&sub->rects);
+
+    memset(sub, 0, sizeof(*sub));
+}
+
diff --git a/libavutil/subfmt.h b/libavutil/subfmt.h
new file mode 100644
index 0000000000..372e3db413
--- /dev/null
+++ b/libavutil/subfmt.h
@@ -0,0 +1,185 @@ 
+/*
+ * Copyright (c) 2021 softworkz
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_SUBFMT_H
+#define AVUTIL_SUBFMT_H
+
+#include <inttypes.h>
+
+#include "buffer.h"
+
+enum AVSubtitleType {
+
+    /**
+     * Subtitle format unknown.
+     */
+    AV_SUBTITLE_FMT_NONE = -1,
+
+    /**
+     * Subtitle format unknown.
+     */
+    AV_SUBTITLE_FMT_UNKNOWN = 0,
+
+    /**
+     * Bitmap area in AVSubtitleRect.data, pixfmt AV_PIX_FMT_PAL8.
+     */
+    AV_SUBTITLE_FMT_BITMAP = 1,
+    SUBTITLE_BITMAP = 1,        ///< Deprecated, use AV_SUBTITLE_FMT_BITMAP instead.
+
+    /**
+     * Plain text in AVSubtitleRect.text.
+     */
+    AV_SUBTITLE_FMT_TEXT = 2,
+    SUBTITLE_TEXT = 2,          ///< Deprecated, use AV_SUBTITLE_FMT_TEXT instead.
+
+    /**
+     * Text Formatted as per ASS specification, contained AVSubtitleRect.ass.
+     */
+    AV_SUBTITLE_FMT_ASS = 3,
+    SUBTITLE_ASS = 3,           ///< Deprecated, use AV_SUBTITLE_FMT_ASS instead.
+
+    AV_SUBTITLE_FMT_NB,
+};
+
+typedef struct AVSubtitleArea {
+#define AV_NUM_BUFFER_POINTERS 1
+
+    enum AVSubtitleType type;
+    int flags;
+
+    int x;         ///< top left corner  of area.
+    int y;         ///< top left corner  of area.
+    int w;         ///< width            of area.
+    int h;         ///< height           of area.
+    int nb_colors; ///< number of colors in bitmap palette (@ref pal).
+
+    /**
+     * Buffers and line sizes for the bitmap of this subtitle.
+     * 
+     * @{
+     */
+    AVBufferRef *buf[AV_NUM_BUFFER_POINTERS];
+    int linesize[AV_NUM_BUFFER_POINTERS];
+    /**
+     * @}
+     */
+
+    uint32_t pal[256]; ///< RGBA palette for the bitmap.
+
+    char *text;        ///< 0-terminated plain UTF-8 text
+    char *ass;         ///< 0-terminated ASS/SSA compatible event line.
+
+} AVSubtitleArea;
+
+typedef struct AVSubtitleRect {
+    unsigned nb_refs;
+    int x;         ///< top left corner  of pict, undefined when pict is not set
+    int y;         ///< top left corner  of pict, undefined when pict is not set
+    int w;         ///< width            of pict, undefined when pict is not set
+    int h;         ///< height           of pict, undefined when pict is not set
+    int nb_colors; ///< number of colors in pict, undefined when pict is not set
+
+    /**
+     * data+linesize for the bitmap of this subtitle.
+     */
+    uint8_t *data[4];
+    int linesize[4];
+
+    enum AVSubtitleType type;
+
+    char *text;                     ///< 0 terminated plain UTF-8 text
+
+    /**
+     * 0-terminated ASS/SSA compatible event line.
+     */
+    char *ass;
+
+    int flags;
+} AVSubtitleRect;
+
+typedef struct AVSubtitle {
+    uint16_t format; /* 0 = graphics */
+    uint32_t start_display_time; /* relative to packet pts, in ms */
+    uint32_t end_display_time; /* relative to packet pts, in ms */
+    unsigned num_rects;
+    AVSubtitleRect **rects;
+    int64_t pts;    ///< Same as packet pts, in AV_TIME_BASE
+} AVSubtitle;
+
+/**
+ * Return the name of sub_fmt, or NULL if sub_fmt is not
+ * recognized.
+ */
+const char *av_get_subtitle_fmt_name(enum AVSubtitleType sub_fmt);
+
+/**
+ * Return a subtitle format corresponding to name, or AV_SUBTITLE_FMT_NONE
+ * on error.
+ *
+ * @param name Subtitle format name.
+ */
+enum AVSubtitleType av_get_subtitle_fmt(const char *name);
+
+/**
+ * Copy a subtitle area.
+ *
+ * @param dst        The target area.
+ * @param src        The source area.
+ * @param copy_data  Determines whether to copy references or actual
+ *                   data from @ref AVSubtitleArea.buf.
+ *
+ * @return 0 on success.
+ */
+int av_subtitle_area2area(AVSubtitleArea *dst, const AVSubtitleArea *src, int copy_data);
+
+/**
+ * Copy data from @ref AVSubtitleArea to @ref AVSubtitleRect.
+ *
+ * @param dst        The target rect (@ref AVSubtitleRect).
+ * @param src        The source area (@ref AVSubtitleArea).
+ *
+ * @return 0 on success.
+ *
+ * @deprecated This is a compatibility method for interoperability with
+ * the legacy subtitle API.
+ */
+int av_subtitle_area2rect(AVSubtitleRect *dst, const AVSubtitleArea *src);
+
+/**
+ * Copy data from @ref AVSubtitleRect to @ref AVSubtitleArea.
+ *
+ * @param dst        The source area (@ref AVSubtitleArea).
+ * @param src        The target rect (@ref AVSubtitleRect).
+ *
+ * @return 0 on success.
+ *
+ * @deprecated This is a compatibility method for interoperability with
+ * the legacy subtitle API.
+ */
+int av_subtitle_rect2area(AVSubtitleArea *dst, const AVSubtitleRect *src);
+
+/**
+ * Free all allocated data in the given subtitle struct.
+ *
+ * @param sub AVSubtitle to free.
+ */
+void avsubtitle_free(AVSubtitle *sub);
+
+#endif /* AVUTIL_SUBFMT_H */