On Sat, 2014-09-13 at 12:36 +0200, Michael Niedermayer wrote: > From: Baptiste Coudurier <baptiste.coudur...@gmail.com> > > Ported by michael from ffmbc to ffmpeg > the code is under CONFIG_GPL as ffmbc is GPL > > Signed-off-by: Michael Niedermayer <michae...@gmx.at> > --- > libavformat/mxfenc.c | 143 > ++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 143 insertions(+)
> +static int mxf_parse_h264_frame(AVFormatContext *s, AVStream *st,
> + AVPacket *pkt, MXFIndexEntry *e)
> +{
> + MXFStreamContext *sc = st->priv_data;
> + H264Context h;
> + const uint8_t *buf = pkt->data;
> + const uint8_t *buf_end = pkt->data + pkt->size;
> + uint32_t state = -1;
> + AVRational sar = {1, 1};
> +
> + if (pkt->size < 5 || AV_RB32(pkt->data) != 0x0000001) {
> + av_log(s, AV_LOG_ERROR, "h264 bitstream malformated, "
> + "no startcode found, use -vbsf h264_mp4toannexb\n");
> + return 0;
> + }
> +
> + memset(&h, 0, sizeof(h));
> + h.avctx = st->codec;
> + h.thread_context[0] = &h;
> + h.prev_frame_num = -1;
> +
> + for (;;) {
> + int src_length, dst_length, consumed;
> + const uint8_t *ptr;
> +
> + buf = avpriv_find_start_code(buf, buf_end, &state);
> + if (buf >= buf_end)
> + break;
> + --buf;
> + src_length = buf_end - buf;
> + switch (state & 0x1f) {
> + case NAL_SLICE:
> + case NAL_IDR_SLICE:
> + // Do not walk the whole buffer just to decode slice header
> + if (src_length > 20)
> + src_length = 20;
> + break;
> + }
> +
> + ptr = ff_h264_decode_nal(&h, buf, &dst_length, &consumed,
> src_length);
> + if (!ptr || dst_length < 0)
> + break;
> +
> + init_get_bits(&h.gb, ptr, 8*dst_length);
> + //av_log(avctx, AV_LOG_DEBUG, "nal_unit_type:%d\n", h.nal_unit_type);
> + switch (h.nal_unit_type) {
> + case NAL_SPS:
> + ff_h264_decode_seq_parameter_set(&h);
> + if (h.sps.sar.num > 0 && h.sps.sar.den > 0) {
> + sar.num = st->codec->width * h.sps.sar.num;
> + sar.den = st->codec->height * h.sps.sar.den;
> + }
> + sc->aspect_ratio.num = st->codec->width * sar.num;
> + sc->aspect_ratio.den = st->codec->height * sar.den;
> + av_reduce(&sc->aspect_ratio.num, &sc->aspect_ratio.den,
> + sar.num, sar.den, 1024*1024);
> +
> + sc->interlaced = !h.sps.frame_mbs_only_flag;
> + sc->component_depth = h.sps.bit_depth_luma;
> +
> + sc->codec_ul = mxf_get_h264_codec_ul(st->codec, &h.sps);
> + e->flags |= 0x40;
> + break;
> + case NAL_PPS:
> + ff_h264_decode_picture_parameter_set(&h, h.gb.size_in_bits);
> + if (h.sps.timing_info_present_flag) {
> + if (st->codec->time_base.num != h.sps.num_units_in_tick ||
> + st->codec->time_base.den*2 != h.sps.time_scale) {
> + av_log(s, AV_LOG_ERROR, "framerate does not match
> bitstream values: %d/%d != %d/%d\n",
> + h.sps.num_units_in_tick, h.sps.time_scale,
> st->codec->time_base.num, st->codec->time_base.den*2);
> + return 0;
> + }
> + }
> + if (e->flags & 0x40) // sequence header present
> + e->flags |= 0x80; // random access
> + break;
> + case NAL_IDR_SLICE:
> + break;
> + case NAL_SLICE:
> + av_log(s, AV_LOG_ERROR, "mxf muxer only supports AVC Intra
> currently\n");
> + return 0;
> + }
> + }
> +
> + return !!sc->codec_ul;
> +}
Seems awfully specific code to have in a muxer. Can this be reused
elsewhere? Don't let that stop you though.
Overall I'm OK with this patch being GPL. It's not optimal, but I
compile with libx264 for my own purposes anyway and thus have GPL
enabled. If someone wants it LGPL bad enough then they're free to
rewrite this of course. Perhaps as a part of making the functionality of
the above function reusable elsewhere? (I think MOV might support
AVC-Intra)
/Tomas
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