Re: [FFmpeg-devel] [PATCH 1/2] avformat/rtpdec_rfc4175: support for interlace format

[lance.lmwang@gmail.com]

On Sun, Jan 02, 2022 at 08:43:30AM +0800, lance.lmwang@gmail.com wrote:
> From: Limin Wang <lance.lmwang@gmail.com>
> 
> Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> ---
> FYI, other patches have submit to support for the interface format few years ago:
> https://patchwork.ffmpeg.org/project/ffmpeg/patch/1531259521-19421-2-git-send-email-patrick.keroulas@savoirfairelinux.com/
> 
> I proposal to process the interlace format from packet level.
> 
>  libavformat/rtpdec_rfc4175.c | 25 +++++++++++++++++++++----
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/libavformat/rtpdec_rfc4175.c b/libavformat/rtpdec_rfc4175.c
> index a66e00d..e0a708e 100644
> --- a/libavformat/rtpdec_rfc4175.c
> +++ b/libavformat/rtpdec_rfc4175.c
> @@ -33,6 +33,8 @@ struct PayloadContext {
>      int depth;
>      int width;
>      int height;
> +    int interlaced;
> +    int field;
>  
>      uint8_t *frame;
>      unsigned int frame_size;
> @@ -104,6 +106,11 @@ static int rfc4175_parse_format(AVStream *stream, PayloadContext *data)
>      stream->codecpar->bits_per_coded_sample = av_get_bits_per_pixel(desc);
>      data->frame_size = data->width * data->height * data->pgroup / data->xinc;
>  
> +    if (data->interlaced)
> +        stream->codecpar->field_order = AV_FIELD_TT;
> +    else
> +        stream->codecpar->field_order = AV_FIELD_PROGRESSIVE;
> +
>      if (data->framerate.den > 0) {
>          stream->avg_frame_rate = data->framerate;
>          stream->codecpar->bit_rate = data->frame_size * av_q2d(data->framerate) * 8;
> @@ -124,6 +131,8 @@ static int rfc4175_parse_fmtp(AVFormatContext *s, AVStream *stream,
>          data->sampling = av_strdup(value);
>      else if (!strncmp(attr, "depth", 5))
>          data->depth = atoi(value);
> +    else if (!strncmp(attr, "interlace", 9))
> +        data->interlaced = 1;
>      else if (!strncmp(attr, "exactframerate", 14)) {
>          if (av_parse_video_rate(&data->framerate, value) < 0)
>              return AVERROR(EINVAL);
> @@ -195,15 +204,18 @@ static int rfc4175_parse_sdp_line(AVFormatContext *s, int st_index,
>  static int rfc4175_finalize_packet(PayloadContext *data, AVPacket *pkt,
>                                     int stream_index)
>  {
> -    int ret;
> +    int ret = 0;
>  
>      pkt->stream_index = stream_index;
> +    if (!data->interlaced || data->field) {
>      ret = av_packet_from_data(pkt, data->frame, data->frame_size);
>      if (ret < 0) {
>          av_freep(&data->frame);
>      }
> -
>      data->frame = NULL;
> +    }
> +
> +    data->field = 0;
>  
>      return ret;
>  }
> @@ -213,7 +225,7 @@ static int rfc4175_handle_packet(AVFormatContext *ctx, PayloadContext *data,
>                                   const uint8_t * buf, int len,
>                                   uint16_t seq, int flags)
>  {
> -    int length, line, offset, cont;
> +    int length, line, offset, cont, field;
>      const uint8_t *headers = buf + 2; /* skip extended seqnum */
>      const uint8_t *payload = buf + 2;
>      int payload_len = len - 2;
> @@ -266,10 +278,12 @@ static int rfc4175_handle_packet(AVFormatContext *ctx, PayloadContext *data,
>              return AVERROR_INVALIDDATA;
>  
>          length = (headers[0] << 8) | headers[1];
> +        field = (headers[2] & 0x80) >> 7;
>          line = ((headers[2] & 0x7f) << 8) | headers[3];
>          offset = ((headers[4] & 0x7f) << 8) | headers[5];
>          cont = headers[4] & 0x80;
>          headers += 6;
> +        data->field = field;
>  
>          if (!data->pgroup || length % data->pgroup)
>              return AVERROR_INVALIDDATA;
> @@ -277,9 +291,12 @@ static int rfc4175_handle_packet(AVFormatContext *ctx, PayloadContext *data,
>          if (length > payload_len)
>              length = payload_len;
>  
> +        if (data->interlaced)
> +            line = 2 * line + field;
> +
>          /* prevent ill-formed packets to write after buffer's end */
>          copy_offset = (line * data->width + offset) * data->pgroup / data->xinc;
> -        if (copy_offset + length > data->frame_size)
> +        if (copy_offset + length > data->frame_size || !data->frame)
>              return AVERROR_INVALIDDATA;
>  
>          dest = data->frame + copy_offset;
> -- 
> 1.8.3.1
> 
ping, please help to test if have other sources from hardware. Now only line number from 0 is supported. 

-- 
Thanks,
Limin Wang
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