[FFmpeg-devel] [PATCH] libx264: copy A53 closed captions from source

[Anshul]

On 09/26/2015 04:16 PM, Anshul wrote:
>
>
> On 09/26/2015 03:57 PM, DeHackEd wrote:
>> On 09/26/2015 05:26 AM, Anshul wrote:
>>>
>>> On 09/26/2015 05:46 AM, DeHackEd wrote:
>>>> Assumes 'GA94' format (ATSC standard)
>>>>
>>>> Signed-off-by: DHE <git at dehacked.net>
>>>> ---
>>>>    doc/encoders.texi    |  5 +++++
>>>>    libavcodec/libx264.c | 37 +++++++++++++++++++++++++++++++++++++
>>>>    2 files changed, 42 insertions(+)
>>>>
>>>> diff --git a/doc/encoders.texi b/doc/encoders.texi
>>>> index 3550bcc..bb16dea 100644
>>>> --- a/doc/encoders.texi
>>>> +++ b/doc/encoders.texi
>>>> @@ -2069,6 +2069,11 @@ For example to specify libx264 encoding 
>>>> options with @command{ffmpeg}:
>>>>    ffmpeg -i foo.mpg -vcodec libx264 -x264opts 
>>>> keyint=123:min-keyint=20 -an out.mkv
>>>>    @end example
>>>>
>>>> + at item a53cc
>>>> +Import closed captions (which must be ATSC compatible format) into 
>>>> output.
>>>> +Only the mpeg2 and h264 decoders provide these. Default is 0 (off).
>>>> +
>>>> +
>>>>    @item x264-params (N.A.)
>>>>    Override the x264 configuration using a :-separated list of 
>>>> key=value
>>>>    parameters.
>>>> diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
>>>> index 58fcfb0..4227bcc 100644
>>>> --- a/libavcodec/libx264.c
>>>> +++ b/libavcodec/libx264.c
>>>> @@ -83,6 +83,7 @@ typedef struct X264Context {
>>>>        int avcintra_class;
>>>>        int motion_est;
>>>>        int forced_idr;
>>>> +    int a53_cc;
>>>>        char *x264_params;
>>>>    } X264Context;
>>>>
>>>> @@ -256,6 +257,7 @@ static int X264_frame(AVCodecContext *ctx, 
>>>> AVPacket *pkt, const AVFrame *frame,
>>>>        int nnal, i, ret;
>>>>        x264_picture_t pic_out = {0};
>>>>        int pict_type;
>>>> +    AVFrameSideData *side_data;
>>>>
>>>>        x264_picture_init( &x4->pic );
>>>>        x4->pic.img.i_csp   = x4->params.i_csp;
>>>> @@ -278,6 +280,40 @@ static int X264_frame(AVCodecContext *ctx, 
>>>> AVPacket *pkt, const AVFrame *frame,
>>>> X264_TYPE_AUTO;
>>>>
>>>>            reconfig_encoder(ctx, frame);
>>>> +
>>>> +        if (x4->a53_cc) {
>>>> +            side_data = av_frame_get_side_data(frame, 
>>>> AV_FRAME_DATA_A53_CC);
>>>> +            if (side_data) {
>>>> +                x4->pic.extra_sei.num_payloads = 1;
>>>> +                x4->pic.extra_sei.payloads = 
>>>> av_mallocz(sizeof(x4->pic.extra_sei.payloads[0]));
>>>> +                x4->pic.extra_sei.sei_free = av_free;
>>>> +
>>>> + x4->pic.extra_sei.payloads[0].payload_size = side_data->size + 11;
>>>> +                x4->pic.extra_sei.payloads[0].payload = 
>>>> av_mallocz(x4->pic.extra_sei.payloads[0].payload_size);
>>>> + x4->pic.extra_sei.payloads[0].payload_type = 4;
>>>> + memcpy(x4->pic.extra_sei.payloads[0].payload + 10, 
>>>> side_data->data, side_data->size);
>>>> +                x4->pic.extra_sei.payloads[0].payload[0] = 181;
>>>> +                x4->pic.extra_sei.payloads[0].payload[1] = 0;
>>>> +                x4->pic.extra_sei.payloads[0].payload[2] = 49;
>>>> +
>>>> +                /**
>>>> +                 * 'GA94' is standard in North America for ATSC, 
>>>> but hard coding
>>>> +                 * this style may not be the right thing to do -- 
>>>> other formats
>>>> +                 * do exist. This information is not available in 
>>>> the side_data
>>>> +                 * so we are going with this right now.
>>>> +                 */
>>> I think GA94 is correct for this situation, since in our x264 
>>> decoder we don't consider any other standard
>>> for extracting closed caption.
>>>
>>> I don't know if we have any logic which differentiate between ATSC, 
>>> ISDB or DVB we parse all transport stream
>>> in same manner. if someone know where we differentiate atsc and dvb 
>>> in FFmpeg please point me there.
>>>
>>> Note: This logic will also fail when x264 is muxed in formats like 
>>> gxf where closed caption are kept in vbi instead
>>> of GA94.
>>>
>>> Overall  LGTM.
>>>
>>> I don't know how to apply encrypted mails using git, and when I save 
>>> your email in Thunderbird, git am is unable to apply.
>>> if you can send the same patch as attachment or command to convert 
>>> encrypted .eml file to normal patch I would test this
>>> too.
>> I think the easiest solution is to grab the patch from the github 
>> repo I use:
>> https://github.com/DeHackEd/FFmpeg/commit/16b4c7fc2311d672e99f.patch
> anshul at linux-z9q9:~/Project/Multimedia/FFmpeg> git apply 
> 16b4c7fc2311d672e99f.patch
> 16b4c7fc2311d672e99f.patch:54: trailing whitespace.
>
> 16b4c7fc2311d672e99f.patch:75: trailing whitespace.
>                  */
> 16b4c7fc2311d672e99f.patch:81: trailing whitespace.
>                 x4->pic.extra_sei.payloads[0].payload[8] =
> warning: 3 lines add whitespace errors.
> anshul at linux-z9q9:~/Project/Multimedia/FFmpeg>
>
> Though I have fixed it at my end to test, but my advice that you fix 
> it too and send another patch.
>
It works fine for me.

-Anshul