[FFmpeg-devel] [PATCH] lavc/videotoolboxenc: implement a53cc

Richard Kern kernrj at gmail.com
Sat Sep 10 21:07:37 EEST 2016


> 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.

>     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.

Thanks for your work. I look forward to an updated patch.

> 
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