[FFmpeg-devel] [PATCH] lavc/videotoolboxenc: implement a53cc
Richard Kern
kernrj at gmail.com
Mon Sep 19 16:27:48 EEST 2016
> On Sep 10, 2016, at 10:33 PM, Aman Gupta <ffmpeg at tmm1.net> wrote:
>
>
>
> On Sunday, September 11, 2016, Richard Kern <kernrj at gmail.com <mailto:kernrj at gmail.com>> wrote:
>
> > On Sep 8, 2016, at 4:19 AM, Aman Gupta <ffmpeg at tmm1.net <>> wrote:
> >
> > From: Aman Gupta <aman at tmm1.net <>>
> >
> > ---
> > libavcodec/videotoolboxenc.c | 76 ++++++++++++++++++++++++++++++++++++++------
> > 1 file changed, 67 insertions(+), 9 deletions(-)
> >
> > diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c
> > index 4345ca3..859dde9 100644
> > --- a/libavcodec/videotoolboxenc.c
> > +++ b/libavcodec/videotoolboxenc.c
> > @@ -32,6 +32,7 @@
> > #include "libavutil/pixdesc.h"
> > #include "internal.h"
> > #include <pthread.h>
> > +#include "h264.h"
> >
> > #if !CONFIG_VT_BT2020
> > # define kCVImageBufferColorPrimaries_ITU_R_2020 CFSTR("ITU_R_2020")
> > @@ -55,8 +56,14 @@ typedef enum VTH264Entropy{
> >
> > static const uint8_t start_code[] = { 0, 0, 0, 1 };
> >
> > +typedef struct ExtraSEI {
> > + void *data;
> > + size_t size;
> > +} ExtraSEI;
> > +
> > typedef struct BufNode {
> > CMSampleBufferRef cm_buffer;
> > + ExtraSEI *sei;
> > struct BufNode* next;
> > int error;
> > } BufNode;
> > @@ -94,6 +101,7 @@ typedef struct VTEncContext {
> > bool flushing;
> > bool has_b_frames;
> > bool warned_color_range;
> > + bool a53_cc;
> > } VTEncContext;
> >
> > static int vtenc_populate_extradata(AVCodecContext *avctx,
> > @@ -136,7 +144,7 @@ static void set_async_error(VTEncContext *vtctx, int err)
> > pthread_mutex_unlock(&vtctx->lock);
> > }
> >
> > -static int vtenc_q_pop(VTEncContext *vtctx, bool wait, CMSampleBufferRef *buf)
> > +static int vtenc_q_pop(VTEncContext *vtctx, bool wait, CMSampleBufferRef *buf, ExtraSEI **sei)
> > {
> > BufNode *info;
> >
> > @@ -173,6 +181,12 @@ static int vtenc_q_pop(VTEncContext *vtctx, bool wait, CMSampleBufferRef *buf)
> > pthread_mutex_unlock(&vtctx->lock);
> >
> > *buf = info->cm_buffer;
> > + if (sei && *buf) {
> > + *sei = info->sei;
> > + } else if (info->sei) {
> > + if (info->sei->data) av_free(info->sei->data);
> > + av_free(info->sei);
> > + }
> > av_free(info);
> >
> > vtctx->frame_ct_out++;
> > @@ -180,7 +194,7 @@ static int vtenc_q_pop(VTEncContext *vtctx, bool wait, CMSampleBufferRef *buf)
> > return 0;
> > }
> >
> > -static void vtenc_q_push(VTEncContext *vtctx, CMSampleBufferRef buffer)
> > +static void vtenc_q_push(VTEncContext *vtctx, CMSampleBufferRef buffer, ExtraSEI *sei)
> > {
> > BufNode *info = av_malloc(sizeof(BufNode));
> > if (!info) {
> > @@ -190,6 +204,7 @@ static void vtenc_q_push(VTEncContext *vtctx, CMSampleBufferRef buffer)
> >
> > CFRetain(buffer);
> > info->cm_buffer = buffer;
> > + info->sei = sei;
> > info->next = NULL;
> >
> > pthread_mutex_lock(&vtctx->lock);
> > @@ -420,6 +435,7 @@ static void vtenc_output_callback(
> > {
> > AVCodecContext *avctx = ctx;
> > VTEncContext *vtctx = avctx->priv_data;
> > + ExtraSEI *sei = sourceFrameCtx;
> >
> > if (vtctx->async_error) {
> > if(sample_buffer) CFRelease(sample_buffer);
> > @@ -440,7 +456,7 @@ static void vtenc_output_callback(
> > }
> > }
> >
> > - vtenc_q_push(vtctx, sample_buffer);
> > + vtenc_q_push(vtctx, sample_buffer, sei);
> > }
> >
> > static int get_length_code_size(
> > @@ -1258,7 +1274,8 @@ static int copy_replace_length_codes(
> > static int vtenc_cm_to_avpacket(
> > AVCodecContext *avctx,
> > CMSampleBufferRef sample_buffer,
> > - AVPacket *pkt)
> > + AVPacket *pkt,
> > + ExtraSEI *sei)
> > {
> > VTEncContext *vtctx = avctx->priv_data;
> >
> > @@ -1269,6 +1286,7 @@ static int vtenc_cm_to_avpacket(
> > size_t header_size = 0;
> > size_t in_buf_size;
> > size_t out_buf_size;
> > + size_t sei_nalu_size = 0;
> > int64_t dts_delta;
> > int64_t time_base_num;
> > int nalu_count;
> > @@ -1298,9 +1316,14 @@ static int vtenc_cm_to_avpacket(
> > if(status)
> > return status;
> >
> > + if (sei) {
> > + sei_nalu_size = sizeof(start_code) + 3 + sei->size + 1;
> > + }
> > +
> > in_buf_size = CMSampleBufferGetTotalSampleSize(sample_buffer);
> > out_buf_size = header_size +
> > in_buf_size +
> > + sei_nalu_size +
> > nalu_count * ((int)sizeof(start_code) - (int)length_code_size);
> >
> > status = ff_alloc_packet2(avctx, pkt, out_buf_size, out_buf_size);
> > @@ -1317,7 +1340,7 @@ static int vtenc_cm_to_avpacket(
> > length_code_size,
> > sample_buffer,
> > pkt->data + header_size,
> > - pkt->size - header_size
> > + pkt->size - header_size - sei_nalu_size
> > );
> >
> > if (status) {
> > @@ -1325,6 +1348,19 @@ static int vtenc_cm_to_avpacket(
> > return status;
> > }
> >
> > + if (sei_nalu_size > 0) {
> > + uint8_t *sei_nalu = pkt->data + pkt->size - sei_nalu_size;
> > + memcpy(sei_nalu, start_code, sizeof(start_code));
> > + sei_nalu += sizeof(start_code);
> > + sei_nalu[0] = NAL_SEI;
> > + sei_nalu[1] = SEI_TYPE_USER_DATA_REGISTERED;
> > + sei_nalu[2] = sei->size;
> > + sei_nalu += 3;
> > + memcpy(sei_nalu, sei->data, sei->size);
> > + sei_nalu += sei->size;
> > + sei_nalu[0] = 1; // RBSP
> > + }
> > +
>
> SEI data should come after the parameter sets and before the other NAL units.
>
> Thanks. I have no prior experience with the h264 bitstream format so the help is much appreciated. Any advice on how to get the SEI inserted at the right spot?
>
> I also am unsure if I need to worry about start code emulation prevention within the SEI data.
The SEI data comes after the parameter sets and AUD NAL units (when they’re present). If I understand correctly, only one SEI NAL unit can be present per access unit (but it can contain multiple SEI messages). When the SEI NAL contains a buffering period SEI message it comes first in the list. The H.264 spec is available from the ITU website and contains the syntax for NAL units, SEI data, etc.
Sorry I’ve been slow getting back to you. Hope this is helpful. If you’d prefer, I can reorder the SEI data later this week.
>
>
> > if (is_key_frame) {
> > pkt->flags |= AV_PKT_FLAG_KEY;
> > }
> > @@ -1707,6 +1743,7 @@ static int vtenc_send_frame(AVCodecContext *avctx,
> > CMTime time;
> > CFDictionaryRef frame_dict;
> > CVPixelBufferRef cv_img = NULL;
> > + ExtraSEI *sei = NULL;
> > int status = create_cv_pixel_buffer(avctx, frame, &cv_img);
> >
> > if (status) return status;
> > @@ -1717,6 +1754,20 @@ static int vtenc_send_frame(AVCodecContext *avctx,
> > return status;
> > }
> >
> > + if (vtctx->a53_cc) {
> > + sei = av_mallocz(sizeof(*sei));
> > + if (!sei) {
> > + av_log(avctx, AV_LOG_ERROR, "Not enough memory for closed captions, skipping\n");
> > + } else {
> > + int ret = ff_alloc_a53_sei(frame, 0, &sei->data, &sei->size);
> > + if (ret < 0) {
> > + av_log(avctx, AV_LOG_ERROR, "Not enough memory for closed captions, skipping\n");
> > + av_free(sei);
> > + sei = NULL;
> > + }
> > + }
> > + }
> > +
> > time = CMTimeMake(frame->pts * avctx->time_base.num, avctx->time_base.den);
> > status = VTCompressionSessionEncodeFrame(
> > vtctx->session,
> > @@ -1724,7 +1775,7 @@ static int vtenc_send_frame(AVCodecContext *avctx,
> > time,
> > kCMTimeInvalid,
> > frame_dict,
> > - NULL,
> > + sei,
> > NULL
> > );
> >
> > @@ -1749,6 +1800,7 @@ static av_cold int vtenc_frame(
> > bool get_frame;
> > int status;
> > CMSampleBufferRef buf = NULL;
> > + ExtraSEI *sei = NULL;
> >
> > if (frame) {
> > status = vtenc_send_frame(avctx, vtctx, frame);
> > @@ -1785,11 +1837,15 @@ static av_cold int vtenc_frame(
> > goto end_nopkt;
> > }
> >
> > - status = vtenc_q_pop(vtctx, !frame, &buf);
> > + status = vtenc_q_pop(vtctx, !frame, &buf, &sei);
> > if (status) goto end_nopkt;
> > if (!buf) goto end_nopkt;
> >
> > - status = vtenc_cm_to_avpacket(avctx, buf, pkt);
> > + status = vtenc_cm_to_avpacket(avctx, buf, pkt, sei);
> > + if (sei) {
> > + if (sei->data) av_free(sei->data);
> > + av_free(sei);
> > + }
> > CFRelease(buf);
> > if (status) goto end_nopkt;
> >
> > @@ -1878,7 +1934,7 @@ static int vtenc_populate_extradata(AVCodecContext *avctx,
> > if (status)
> > goto pe_cleanup;
> >
> > - status = vtenc_q_pop(vtctx, 0, &buf);
> > + status = vtenc_q_pop(vtctx, 0, &buf, NULL);
> > if (status) {
> > av_log(avctx, AV_LOG_ERROR, "popping: %d\n", status);
> > goto pe_cleanup;
> > @@ -1976,6 +2032,8 @@ static const AVOption options[] = {
> > { "frames_after", "Other frames will come after the frames in this session. This helps smooth concatenation issues.",
> > OFFSET(frames_after), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VE },
> >
> > + { "a53cc", "Use A53 Closed Captions (if available)", OFFSET(a53_cc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, VE },
> > +
> > { NULL },
> > };
> >
> > --
> > 2.8.1
>
> Patches should be made against the latest master branch. It doesn’t compile as-is.
>
> Oops, rebased locally for next patch.
>
>
> Thanks for your work. I look forward to an updated patch.
>
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > <>ffmpeg-devel at ffmpeg.org <mailto:ffmpeg-devel at ffmpeg.org>
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel <http://ffmpeg.org/mailman/listinfo/ffmpeg-devel>
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