On 10 April 2018 at 22:21, Patrick Keroulas <
patrick.kerou...@savoirfairelinux.com> wrote:
> From: Damien Riegel <damien.rie...@savoirfairelinux.com>
>
> In order to handle the interlaced formats, the demuxer has only a few
> things to do:
> - parse the SDP correctly and propagate the information
> - check the field bit in the RFC4175 header, and pass that information
> to the decoder
>
> In interlaced mode, received data only consist of fields, and their
> heights are half of the frame size, so some adjustments must be done
> here and there to take that into account.
>
> Signed-off-by: Damien Riegel <damien.rie...@savoirfairelinux.com>
> ---
> libavformat/rtpdec_rfc4175.c | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/rtpdec_rfc4175.c b/libavformat/rtpdec_rfc4175.c
> index e9c62c1..55a36eb 100644
> --- a/libavformat/rtpdec_rfc4175.c
> +++ b/libavformat/rtpdec_rfc4175.c
> @@ -31,6 +31,8 @@ struct PayloadContext {
> int depth;
> int width;
> int height;
> + int interlaced;
> + int field;
>
> uint8_t *frame;
> unsigned int frame_size;
> @@ -65,10 +67,18 @@ static int rfc4175_parse_format(AVStream *stream,
> PayloadContext *data)
> return AVERROR_INVALIDDATA;
> }
>
> + if (data->interlaced)
> + stream->codecpar->field_order = AV_FIELD_TT;
> + else
> + stream->codecpar->field_order = AV_FIELD_PROGRESSIVE;
> +
> stream->codecpar->format = pixfmt;
> stream->codecpar->codec_tag = tag;
> stream->codecpar->bits_per_coded_sample = bits_per_sample;
> - data->frame_size = data->width * data->height * data->pgroup /
> data->xinc;
> + if (data->interlaced)
> + data->frame_size = data->width * (data->height / 2) *
> data->pgroup / data->xinc;
> + else
> + data->frame_size = data->width * data->height * data->pgroup /
> data->xinc;
>
> return 0;
> }
> @@ -85,6 +95,8 @@ 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;
>
> return 0;
> }
> @@ -131,7 +143,11 @@ static int rfc4175_finalize_packet(PayloadContext
> *data, AVPacket *pkt,
> av_freep(&data->frame);
> }
>
> + /* In the packet header, the field is set to 0 for top field
> + * and 1 for bottom */
> + pkt->flags |= data->field ? 0 : AV_PKT_FLAG_TOP_FIELD;
> data->frame = NULL;
> + data->field = 0;
>
> return ret;
> }
> @@ -141,7 +157,7 @@ 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;
> @@ -194,11 +210,14 @@ static int rfc4175_handle_packet(AVFormatContext
> *ctx, PayloadContext *data,
> return AVERROR_INVALIDDATA;
>
> length = (headers[0] << 8) | headers[1];
> + field = (headers[2] & 0x80);
> line = ((headers[2] & 0x7f) << 8) | headers[3];
> offset = ((headers[4] & 0x7f) << 8) | headers[5];
> cont = headers[4] & 0x80;
> headers += 6;
>
> + data->field = field;
> +
> if (length % data->pgroup)
> return AVERROR_INVALIDDATA;
>
> --
> 2.7.4
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
Needs to use the bottom field packet flag too.
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