[FFmpeg-devel] avcodec: add truehd_core bitstream filter

Submitted by Paul B Mahol on Nov. 20, 2018, 6:17 p.m.

Details

Message ID 20181120181702.17988-1-onemda@gmail.com
State New
Headers show

Commit Message

Paul B Mahol Nov. 20, 2018, 6:17 p.m.
Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
 doc/bitstream_filters.texi     |   4 +
 libavcodec/Makefile            |   1 +
 libavcodec/bitstream_filters.c |   1 +
 libavcodec/truehd_core_bsf.c   | 182 +++++++++++++++++++++++++++++++++
 4 files changed, 188 insertions(+)
 create mode 100644 libavcodec/truehd_core_bsf.c

Comments

James Almer Nov. 21, 2018, 2:29 a.m.
On 11/20/2018 3:17 PM, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda@gmail.com>
> ---
>  doc/bitstream_filters.texi     |   4 +
>  libavcodec/Makefile            |   1 +
>  libavcodec/bitstream_filters.c |   1 +
>  libavcodec/truehd_core_bsf.c   | 182 +++++++++++++++++++++++++++++++++
>  4 files changed, 188 insertions(+)
>  create mode 100644 libavcodec/truehd_core_bsf.c
> 
> diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
> index 655a2c1e63..15c578aa8a 100644
> --- a/doc/bitstream_filters.texi
> +++ b/doc/bitstream_filters.texi
> @@ -634,6 +634,10 @@ This can be useful for debugging low-level stream issues.
>  
>  Supports H.264, H.265, MPEG-2 and VP9.
>  
> +@section truehd_core
> +
> +Extract the core from a TrueHD stream, dropping ATMOS data.
> +
>  @section vp9_metadata
>  
>  Modify metadata embedded in a VP9 stream.
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 716f26d191..bcced2e371 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -1085,6 +1085,7 @@ OBJS-$(CONFIG_PRORES_METADATA_BSF)        += prores_metadata_bsf.o
>  OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF)       += remove_extradata_bsf.o
>  OBJS-$(CONFIG_TEXT2MOVSUB_BSF)            += movsub_bsf.o
>  OBJS-$(CONFIG_TRACE_HEADERS_BSF)          += trace_headers_bsf.o
> +OBJS-$(CONFIG_TRUEHD_CORE_BSF)            += truehd_core_bsf.o
>  OBJS-$(CONFIG_VP9_METADATA_BSF)           += vp9_metadata_bsf.o
>  OBJS-$(CONFIG_VP9_RAW_REORDER_BSF)        += vp9_raw_reorder_bsf.o
>  OBJS-$(CONFIG_VP9_SUPERFRAME_BSF)         += vp9_superframe_bsf.o
> diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
> index 2a8598bac2..2c999d3c1d 100644
> --- a/libavcodec/bitstream_filters.c
> +++ b/libavcodec/bitstream_filters.c
> @@ -51,6 +51,7 @@ extern const AVBitStreamFilter ff_prores_metadata_bsf;
>  extern const AVBitStreamFilter ff_remove_extradata_bsf;
>  extern const AVBitStreamFilter ff_text2movsub_bsf;
>  extern const AVBitStreamFilter ff_trace_headers_bsf;
> +extern const AVBitStreamFilter ff_truehd_core_bsf;
>  extern const AVBitStreamFilter ff_vp9_metadata_bsf;
>  extern const AVBitStreamFilter ff_vp9_raw_reorder_bsf;
>  extern const AVBitStreamFilter ff_vp9_superframe_bsf;
> diff --git a/libavcodec/truehd_core_bsf.c b/libavcodec/truehd_core_bsf.c
> new file mode 100644
> index 0000000000..0449719185
> --- /dev/null
> +++ b/libavcodec/truehd_core_bsf.c
> @@ -0,0 +1,182 @@
> +/*
> + * Copyright (c) 2018 Paul B Mahol
> + *
> + * 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 "avcodec.h"
> +#include "bsf.h"
> +#include "get_bits.h"
> +#include "mlp_parser.h"
> +#include "mlp.h"

Missing deps in configure or Makefile for mlp parser and whatever else
is needed.

> +
> +typedef struct AccessUnit {
> +    uint8_t bits[4];
> +    uint16_t offset;
> +    uint16_t optional;
> +} AccessUnit;
> +
> +typedef struct TrueHDCoreContext {
> +    const AVClass *class;
> +
> +    AccessUnit units[4];

If this is going to be overwritten on every frame and old state doesn't
matter, then allocate it on stack.

> +
> +    MLPHeaderInfo hdr;
> +} TrueHDCoreContext;
> +
> +static int truehd_core_filter(AVBSFContext *ctx, AVPacket *out)
> +{
> +    TrueHDCoreContext *s = ctx->priv_data;
> +    GetBitContext gbc;
> +    AVPacket *in;
> +    int ret, i, size, last_offset = 0;
> +    int in_size, out_size;
> +    int have_header = 0;
> +    int substream_bits = 0;
> +    int start, end;
> +    uint16_t dts;
> +
> +    ret = ff_bsf_get_packet(ctx, &in);
> +    if (ret < 0)
> +        return ret;
> +
> +    ret = init_get_bits8(&gbc, in->data, 4);

No need for init_get_bits8() if it's going to be 4 bytes. Use
init_get_bits() and skip all the pointless overflow checks.

> +    if (ret < 0)
> +        goto fail;
> +
> +    skip_bits(&gbc, 4);
> +    in_size = get_bits(&gbc, 12) * 2;
> +    if (in_size < 4 || in_size > in->size)
> +        goto fail;
> +
> +    out_size = in_size;
> +    dts = get_bits(&gbc, 16);
> +
> +    ret = init_get_bits8(&gbc, in->data + 4, in->size - 4);
> +    if (ret < 0)
> +        goto fail;
> +
> +    if (show_bits_long(&gbc, 32) == 0xf8726fba) {
> +        if ((ret = ff_mlp_read_major_sync(ctx, &s->hdr, &gbc)) != 0)
> +            goto fail;
> +        have_header = 1;
> +    }
> +
> +    start = get_bits_count(&gbc);
> +    for (i = 0; i < s->hdr.num_substreams; i++) {
> +        for (int j = 0; j < 4; j++)
> +            s->units[i].bits[j] = get_bits1(&gbc);
> +
> +        s->units[i].offset = get_bits(&gbc, 12) * 2;
> +        if (i < FFMIN(s->hdr.num_substreams, 3)) {
> +            last_offset = s->units[i].offset;
> +            substream_bits += 16;
> +        }
> +
> +        if (s->units[i].bits[0]) {
> +            s->units[i].optional = get_bits(&gbc, 16);
> +            if (i < FFMIN(s->hdr.num_substreams, 3))
> +                substream_bits += 16;
> +        }
> +    }
> +    end = get_bits_count(&gbc);
> +
> +    ret = av_packet_copy_props(out, in);

Move this to the end. See below.

> +    if (ret < 0)
> +        goto fail;
> +
> +    size = ((end + 7) >> 3) + 4 + last_offset;
> +    if (size >= 0 && size <= in->size)
> +        out_size = size;
> +    ret = av_grow_packet(out, out_size);

out is clear/unallocated , so use av_new_packet() instead, and put it...

> +    if (ret < 0)
> +        goto fail;
> +
> +    if (out_size < in_size) {
> +        int bpos = 0, reduce = (end - start - substream_bits) >> 4;
> +        uint16_t parity_nibble = 0;
> +        uint16_t auheader;
> +

...here.

> +        AV_WB16(out->data + 2, dts);
> +        parity_nibble = dts;
> +        out->size -= reduce * 2;
> +        parity_nibble ^= out->size / 2;
> +
> +        if (have_header) {
> +            memcpy(out->data + 4, in->data + 4, 28);
> +            out->data[16 + 4] = (out->data[16 + 4] & 0x0f) | (FFMIN(s->hdr.num_substreams, 3) << 4);
> +            out->data[25 + 4] = out->data[25 + 4] & 0xfe;
> +            out->data[26 + 4] = 0xff;
> +            out->data[27 + 4] = 0xff;
> +            AV_WL16(out->data + 4 + 26, ff_mlp_checksum16(out->data + 4, 26));
> +        }
> +
> +        for (i = 0; i < FFMIN(s->hdr.num_substreams, 3); i++) {
> +            uint16_t substr_hdr = 0;
> +
> +            substr_hdr |= (s->units[i].bits[0] << 15);
> +            substr_hdr |= (s->units[i].bits[1] << 14);
> +            substr_hdr |= (s->units[i].bits[2] << 13);
> +            substr_hdr |= (s->units[i].bits[3] << 12);
> +            substr_hdr |= (s->units[i].offset / 2) & 0x0FFF;
> +
> +            AV_WB16(out->data + have_header * 28 + 4 + bpos, substr_hdr);
> +
> +            parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
> +            parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
> +
> +            if (s->units[i].bits[0]) {
> +                AV_WB16(out->data + have_header * 28 + 4 + bpos, s->units[i].optional);
> +
> +                parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
> +                parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
> +            }
> +        }
> +
> +        parity_nibble ^= parity_nibble >> 8;
> +        parity_nibble ^= parity_nibble >> 4;
> +        parity_nibble &= 0xF;
> +
> +        memcpy(out->data + have_header * 28 + 4 + bpos,
> +               in->data + 4 + (end >> 3),
> +               out_size - (4 + (end >> 3)));
> +        auheader  = (parity_nibble ^ 0xF) << 12;
> +        auheader |= (out->size / 2) & 0x0fff;
> +        AV_WB16(out->data, auheader);

Put the av_packet_copy_props() call here.

> +    } else {
> +        memcpy(out->data, in->data, out_size);

av_packet_move_ref(out, in);
out->size = out_size;

There's no need to allocate and copy data and props when the output
packet is going to be the same as the input.

> +    }
> +
> +    av_packet_free(&in);
> +
> +    return 0;
> +fail:
> +    av_packet_unref(out);
> +    av_packet_free(&in);
> +    return ret;

Combine this for both failure and success cases. Check for ret < 0 to
call av_packet_unref(out), and return ret regardless of value.

> +}
> +
> +static const enum AVCodecID codec_ids[] = {
> +    AV_CODEC_ID_TRUEHD, AV_CODEC_ID_NONE,
> +};
> +
> +const AVBitStreamFilter ff_truehd_core_bsf = {
> +    .name           = "truehd_core",
> +    .priv_data_size = sizeof(TrueHDCoreContext),
> +    .filter         = truehd_core_filter,
> +    .codec_ids      = codec_ids,
> +};
>

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diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index 655a2c1e63..15c578aa8a 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -634,6 +634,10 @@  This can be useful for debugging low-level stream issues.
 
 Supports H.264, H.265, MPEG-2 and VP9.
 
+@section truehd_core
+
+Extract the core from a TrueHD stream, dropping ATMOS data.
+
 @section vp9_metadata
 
 Modify metadata embedded in a VP9 stream.
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 716f26d191..bcced2e371 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1085,6 +1085,7 @@  OBJS-$(CONFIG_PRORES_METADATA_BSF)        += prores_metadata_bsf.o
 OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF)       += remove_extradata_bsf.o
 OBJS-$(CONFIG_TEXT2MOVSUB_BSF)            += movsub_bsf.o
 OBJS-$(CONFIG_TRACE_HEADERS_BSF)          += trace_headers_bsf.o
+OBJS-$(CONFIG_TRUEHD_CORE_BSF)            += truehd_core_bsf.o
 OBJS-$(CONFIG_VP9_METADATA_BSF)           += vp9_metadata_bsf.o
 OBJS-$(CONFIG_VP9_RAW_REORDER_BSF)        += vp9_raw_reorder_bsf.o
 OBJS-$(CONFIG_VP9_SUPERFRAME_BSF)         += vp9_superframe_bsf.o
diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index 2a8598bac2..2c999d3c1d 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -51,6 +51,7 @@  extern const AVBitStreamFilter ff_prores_metadata_bsf;
 extern const AVBitStreamFilter ff_remove_extradata_bsf;
 extern const AVBitStreamFilter ff_text2movsub_bsf;
 extern const AVBitStreamFilter ff_trace_headers_bsf;
+extern const AVBitStreamFilter ff_truehd_core_bsf;
 extern const AVBitStreamFilter ff_vp9_metadata_bsf;
 extern const AVBitStreamFilter ff_vp9_raw_reorder_bsf;
 extern const AVBitStreamFilter ff_vp9_superframe_bsf;
diff --git a/libavcodec/truehd_core_bsf.c b/libavcodec/truehd_core_bsf.c
new file mode 100644
index 0000000000..0449719185
--- /dev/null
+++ b/libavcodec/truehd_core_bsf.c
@@ -0,0 +1,182 @@ 
+/*
+ * Copyright (c) 2018 Paul B Mahol
+ *
+ * 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 "avcodec.h"
+#include "bsf.h"
+#include "get_bits.h"
+#include "mlp_parser.h"
+#include "mlp.h"
+
+typedef struct AccessUnit {
+    uint8_t bits[4];
+    uint16_t offset;
+    uint16_t optional;
+} AccessUnit;
+
+typedef struct TrueHDCoreContext {
+    const AVClass *class;
+
+    AccessUnit units[4];
+
+    MLPHeaderInfo hdr;
+} TrueHDCoreContext;
+
+static int truehd_core_filter(AVBSFContext *ctx, AVPacket *out)
+{
+    TrueHDCoreContext *s = ctx->priv_data;
+    GetBitContext gbc;
+    AVPacket *in;
+    int ret, i, size, last_offset = 0;
+    int in_size, out_size;
+    int have_header = 0;
+    int substream_bits = 0;
+    int start, end;
+    uint16_t dts;
+
+    ret = ff_bsf_get_packet(ctx, &in);
+    if (ret < 0)
+        return ret;
+
+    ret = init_get_bits8(&gbc, in->data, 4);
+    if (ret < 0)
+        goto fail;
+
+    skip_bits(&gbc, 4);
+    in_size = get_bits(&gbc, 12) * 2;
+    if (in_size < 4 || in_size > in->size)
+        goto fail;
+
+    out_size = in_size;
+    dts = get_bits(&gbc, 16);
+
+    ret = init_get_bits8(&gbc, in->data + 4, in->size - 4);
+    if (ret < 0)
+        goto fail;
+
+    if (show_bits_long(&gbc, 32) == 0xf8726fba) {
+        if ((ret = ff_mlp_read_major_sync(ctx, &s->hdr, &gbc)) != 0)
+            goto fail;
+        have_header = 1;
+    }
+
+    start = get_bits_count(&gbc);
+    for (i = 0; i < s->hdr.num_substreams; i++) {
+        for (int j = 0; j < 4; j++)
+            s->units[i].bits[j] = get_bits1(&gbc);
+
+        s->units[i].offset = get_bits(&gbc, 12) * 2;
+        if (i < FFMIN(s->hdr.num_substreams, 3)) {
+            last_offset = s->units[i].offset;
+            substream_bits += 16;
+        }
+
+        if (s->units[i].bits[0]) {
+            s->units[i].optional = get_bits(&gbc, 16);
+            if (i < FFMIN(s->hdr.num_substreams, 3))
+                substream_bits += 16;
+        }
+    }
+    end = get_bits_count(&gbc);
+
+    ret = av_packet_copy_props(out, in);
+    if (ret < 0)
+        goto fail;
+
+    size = ((end + 7) >> 3) + 4 + last_offset;
+    if (size >= 0 && size <= in->size)
+        out_size = size;
+    ret = av_grow_packet(out, out_size);
+    if (ret < 0)
+        goto fail;
+
+    if (out_size < in_size) {
+        int bpos = 0, reduce = (end - start - substream_bits) >> 4;
+        uint16_t parity_nibble = 0;
+        uint16_t auheader;
+
+        AV_WB16(out->data + 2, dts);
+        parity_nibble = dts;
+        out->size -= reduce * 2;
+        parity_nibble ^= out->size / 2;
+
+        if (have_header) {
+            memcpy(out->data + 4, in->data + 4, 28);
+            out->data[16 + 4] = (out->data[16 + 4] & 0x0f) | (FFMIN(s->hdr.num_substreams, 3) << 4);
+            out->data[25 + 4] = out->data[25 + 4] & 0xfe;
+            out->data[26 + 4] = 0xff;
+            out->data[27 + 4] = 0xff;
+            AV_WL16(out->data + 4 + 26, ff_mlp_checksum16(out->data + 4, 26));
+        }
+
+        for (i = 0; i < FFMIN(s->hdr.num_substreams, 3); i++) {
+            uint16_t substr_hdr = 0;
+
+            substr_hdr |= (s->units[i].bits[0] << 15);
+            substr_hdr |= (s->units[i].bits[1] << 14);
+            substr_hdr |= (s->units[i].bits[2] << 13);
+            substr_hdr |= (s->units[i].bits[3] << 12);
+            substr_hdr |= (s->units[i].offset / 2) & 0x0FFF;
+
+            AV_WB16(out->data + have_header * 28 + 4 + bpos, substr_hdr);
+
+            parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+            parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+
+            if (s->units[i].bits[0]) {
+                AV_WB16(out->data + have_header * 28 + 4 + bpos, s->units[i].optional);
+
+                parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+                parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
+            }
+        }
+
+        parity_nibble ^= parity_nibble >> 8;
+        parity_nibble ^= parity_nibble >> 4;
+        parity_nibble &= 0xF;
+
+        memcpy(out->data + have_header * 28 + 4 + bpos,
+               in->data + 4 + (end >> 3),
+               out_size - (4 + (end >> 3)));
+        auheader  = (parity_nibble ^ 0xF) << 12;
+        auheader |= (out->size / 2) & 0x0fff;
+        AV_WB16(out->data, auheader);
+    } else {
+        memcpy(out->data, in->data, out_size);
+    }
+
+    av_packet_free(&in);
+
+    return 0;
+fail:
+    av_packet_unref(out);
+    av_packet_free(&in);
+    return ret;
+}
+
+static const enum AVCodecID codec_ids[] = {
+    AV_CODEC_ID_TRUEHD, AV_CODEC_ID_NONE,
+};
+
+const AVBitStreamFilter ff_truehd_core_bsf = {
+    .name           = "truehd_core",
+    .priv_data_size = sizeof(TrueHDCoreContext),
+    .filter         = truehd_core_filter,
+    .codec_ids      = codec_ids,
+};