[FFmpeg-devel,v6,2/3] avcodec/bitpacked: add interlace support

Submitted by Patrick Keroulas on May 14, 2018, 10:26 p.m.

Details

Message ID 1526336797-21703-2-git-send-email-patrick.keroulas@savoirfairelinux.com
State New
Headers show

Commit Message

Patrick Keroulas May 14, 2018, 10:26 p.m.
From: Damien Riegel <damien.riegel@savoirfairelinux.com>

This codec is already capable of depacking some combinations of pixel
formats and depth as defined in the RFC4175. The only difference between
progressive and interlace is that either a packet will contain the whole
frame, or only a field of the frame.

There is no mechanism for interlaced frames reconstruction at the rtp
demux level, so it has to be handled by the codec which needs to
partially recompose an AVFrame with every incoming field AVPacket.
A frame is ouput only when the frame is completed with the 2nd field
(bottom).

The additionnal field flags in AVPacket allow the decoder to dynamically
determine the frame format, i.e. progressive or interlaced.

Signed-off-by: Patrick Keroulas <patrick.keroulas@savoirfairelinux.com>
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
---

Changes v5 -> v6:
 * cleanup
 * move the packet flags in a separate patch
 * bump lavc minor version in this new patch
---
 libavcodec/bitpacked.c | 122 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 103 insertions(+), 19 deletions(-)

Patch hide | download patch | download mbox

diff --git a/libavcodec/bitpacked.c b/libavcodec/bitpacked.c
index f0b417d..4157876 100644
--- a/libavcodec/bitpacked.c
+++ b/libavcodec/bitpacked.c
@@ -32,8 +32,9 @@ 
 #include "libavutil/imgutils.h"
 
 struct BitpackedContext {
-    int (*decode)(AVCodecContext *avctx, AVFrame *frame,
-                  AVPacket *pkt);
+    int (*decode)(AVCodecContext *avctx, AVFrame *frame, AVPacket *pkt);
+    AVFrame *cur_interlaced_frame;
+    int prev_top_field;
 };
 
 /* For this format, it's a simple passthrough */
@@ -58,27 +59,41 @@  static int bitpacked_decode_uyvy422(AVCodecContext *avctx, AVFrame *frame,
 static int bitpacked_decode_yuv422p10(AVCodecContext *avctx, AVFrame *frame,
                                       AVPacket *avpkt)
 {
-    uint64_t frame_size = (uint64_t)avctx->width * (uint64_t)avctx->height * 20;
+    uint64_t frame_size = avctx->width * avctx->height * 20LL;
     uint64_t packet_size = (uint64_t)avpkt->size * 8;
+    int interlaced = frame->interlaced_frame;
+    int top_field = (avpkt->flags & AV_PKT_FLAG_TOP_FIELD) ? 1 : 0;
     GetBitContext bc;
     uint16_t *y, *u, *v;
     int ret, i, j;
 
-    ret = ff_get_buffer(avctx, frame, 0);
-    if (ret < 0)
-        return ret;
-
-    if (frame_size > packet_size)
+    /* check packet size depending on the interlaced/progressive format */
+    if (interlaced) {
+        if ((frame_size / 2) > packet_size)
+            return AVERROR_INVALIDDATA;
+    } else if (frame_size > packet_size) {
         return AVERROR_INVALIDDATA;
+    }
 
     if (avctx->width % 2)
         return AVERROR_PATCHWELCOME;
 
-    ret = init_get_bits(&bc, avpkt->data, avctx->width * avctx->height * 20);
+    /*
+     * if the frame is interlaced, the avpkt we are getting is either the top
+     * or the bottom field. If it's the bottom field, it contains all the odd
+     * lines of the recomposed frame, so we start at offset 1.
+     */
+    i = (interlaced && !top_field) ? 1 : 0;
+
+    ret = init_get_bits(&bc, avpkt->data, frame_size);
     if (ret)
         return ret;
 
-    for (i = 0; i < avctx->height; i++) {
+    /*
+     * Packets from interlaced frames contain either even lines, or odd
+     * lines, so increment by two in that case.
+     */
+    for (; i < avctx->height; i += 1 + interlaced) {
         y = (uint16_t*)(frame->data[0] + i * frame->linesize[0]);
         u = (uint16_t*)(frame->data[1] + i * frame->linesize[1]);
         v = (uint16_t*)(frame->data[2] + i * frame->linesize[2]);
@@ -103,17 +118,35 @@  static av_cold int bitpacked_init_decoder(AVCodecContext *avctx)
 
     if (avctx->codec_tag == MKTAG('U', 'Y', 'V', 'Y')) {
         if (avctx->bits_per_coded_sample == 16 &&
-            avctx->pix_fmt == AV_PIX_FMT_UYVY422)
+            avctx->pix_fmt == AV_PIX_FMT_UYVY422) {
+
+            if (avctx->field_order > AV_FIELD_PROGRESSIVE) {
+                av_log(avctx, AV_LOG_ERROR, "interlaced not yet supported for 8-bit\n");
+                return AVERROR_PATCHWELCOME;
+            }
+
             bc->decode = bitpacked_decode_uyvy422;
-        else if (avctx->bits_per_coded_sample == 20 &&
-                 avctx->pix_fmt == AV_PIX_FMT_YUV422P10)
+        } else if (avctx->bits_per_coded_sample == 20 &&
+                 avctx->pix_fmt == AV_PIX_FMT_YUV422P10) {
             bc->decode = bitpacked_decode_yuv422p10;
-        else
+        } else {
             return AVERROR_INVALIDDATA;
+        }
     } else {
         return AVERROR_INVALIDDATA;
     }
 
+    bc->cur_interlaced_frame = av_frame_alloc();
+
+    return 0;
+}
+
+static av_cold int bitpacked_end_decoder(AVCodecContext *avctx)
+{
+    struct BitpackedContext *bc = avctx->priv_data;
+
+    av_frame_free(&bc->cur_interlaced_frame);
+
     return 0;
 }
 
@@ -128,13 +161,63 @@  static int bitpacked_decode(AVCodecContext *avctx, void *data, int *got_frame,
     frame->pict_type = AV_PICTURE_TYPE_I;
     frame->key_frame = 1;
 
-    res = bc->decode(avctx, frame, avpkt);
-    if (res)
-        return res;
+    if ((avpkt->flags & AV_PKT_FLAG_TOP_FIELD) &&
+        (avpkt->flags & AV_PKT_FLAG_BOTTOM_FIELD)) {
+        av_log(avctx, AV_LOG_WARNING, "Invalid field flags.\n");
+        return AVERROR_INVALIDDATA;
+    } else if (avpkt->flags & AV_PKT_FLAG_TOP_FIELD) {
+        frame->interlaced_frame = 1;
+        frame->top_field_first = 1;
+
+        if((res = ff_get_buffer(avctx, frame, 0)) < 0)
+            return res;
+
+        /* always decode the top (1st) field and ref the result frame
+         * but don't output anything */
+        if ((res = bc->decode(avctx, frame, avpkt)) < 0)
+            return res;
+
+        av_frame_unref(bc->cur_interlaced_frame);
+        if ((res = av_frame_ref(bc->cur_interlaced_frame, frame)) < 0)
+            return res;
+
+        bc->prev_top_field = 1;
+
+        return 0;
+    } else if (avpkt->flags & AV_PKT_FLAG_BOTTOM_FIELD) {
+        if (!bc->prev_top_field) {
+            av_log(avctx, AV_LOG_ERROR, "Top field missing.\n");
+            return AVERROR_INVALIDDATA;
+        }
 
-    *got_frame = 1;
-    return buf_size;
+        frame->interlaced_frame = 1;
+        frame->top_field_first = 1;
 
+        /* complete the ref'd frame with bottom field and output the
+         * result */
+        if ((res = bc->decode(avctx, bc->cur_interlaced_frame, avpkt)) < 0)
+            return res;
+
+        if ((res = av_frame_ref(frame, bc->cur_interlaced_frame)) < 0)
+            return res;
+
+        bc->prev_top_field = 0;
+        *got_frame = 1;
+        return buf_size;
+    } else {
+        /* No field: the frame is progressive. */
+        if (bc->prev_top_field)
+            av_frame_unref(bc->cur_interlaced_frame);
+
+        if((res = ff_get_buffer(avctx, frame, 0)) < 0)
+            return res;
+
+        if ((res = bc->decode(avctx, frame, avpkt)) < 0)
+            return res;
+
+        *got_frame = 1;
+        return buf_size;
+    }
 }
 
 AVCodec ff_bitpacked_decoder = {
@@ -144,6 +227,7 @@  AVCodec ff_bitpacked_decoder = {
     .id = AV_CODEC_ID_BITPACKED,
     .priv_data_size        = sizeof(struct BitpackedContext),
     .init = bitpacked_init_decoder,
+    .close = bitpacked_end_decoder,
     .decode = bitpacked_decode,
     .capabilities = AV_CODEC_CAP_EXPERIMENTAL,
 };