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

Aman Gupta ffmpeg at tmm1.net
Mon Oct 24 09:17:46 EEST 2016


On Monday, September 19, 2016, Richard Kern <kernrj at gmail.com> wrote:

>
> On Sep 10, 2016, at 10:33 PM, Aman Gupta <ffmpeg at tmm1.net
> <javascript:_e(%7B%7D,'cvml','ffmpeg at tmm1.net');>> wrote:
>
>
>
> On Sunday, September 11, 2016, Richard Kern <kernrj at gmail.com
> <javascript:_e(%7B%7D,'cvml','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.
>

No problem. If you get a chance to work up a patch, I would very much
appreciate it.



>
>
>
>>
>> >     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
>> <javascript:_e(%7B%7D,'cvml','ffmpeg-devel at ffmpeg.org');>
>> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
>
>


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