[FFmpeg-devel] [PATCH 1/1] avformat/matroska: fully parse stsd atom in v_quicktime tracks
Michael Niedermayer
michael at niedermayer.cc
Thu Aug 15 00:50:44 EEST 2019
On Wed, Aug 14, 2019 at 08:44:11PM +0200, Stanislav Ionascu wrote:
> On Tue, Aug 13, 2019 at 10:22 PM Andreas Rheinhardt
> <andreas.rheinhardt at gmail.com> wrote:
> >
> > Stanislav Ionascu:
> > > Per matroska spec, v_quicktime contains the complete stsd atom, after
> > > the mandatory size + fourcc. By properly parsing the hvcc sub-atoms of
> > > the track, it becomes possible to demux/decode mp4/mov tracks stored as is
> > > in matroska containers.
> > >
> > > Also dvh1 in stsd in matroska is more likely hevc codec than dv.
> > >
> > > Signed-off-by: Stanislav Ionascu <stanislav.ionascu at gmail.com>
> > > ---
> > > libavformat/matroskadec.c | 51 +++++++++++++++++++++++++++------------
> > > 1 file changed, 36 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
> > > index 4e20f15792..88bc89c545 100644
> > > --- a/libavformat/matroskadec.c
> > > +++ b/libavformat/matroskadec.c
> > > @@ -2473,25 +2473,46 @@ static int matroska_parse_tracks(AVFormatContext *s)
> > > } else if (!strcmp(track->codec_id, "V_QUICKTIME") &&
> > > (track->codec_priv.size >= 21) &&
> > > (track->codec_priv.data)) {
> > > + MOVStreamContext *msc;
> > > + MOVContext *mc = NULL;
> > > + AVIOContext *stsd_ctx = NULL;
> > > + void *priv_data;
> > > + int nb_streams;
> > > int ret = get_qt_codec(track, &fourcc, &codec_id);
> > > if (ret < 0)
> > > return ret;
> > > - if (codec_id == AV_CODEC_ID_NONE && AV_RL32(track->codec_priv.data+4) == AV_RL32("SMI ")) {
> > > - fourcc = MKTAG('S','V','Q','3');
> > > - codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
> > > + av_log(matroska->ctx, AV_LOG_TRACE,
> > > + "FourCC found %s.\n", av_fourcc2str(fourcc));
> > > + priv_data = st->priv_data;
> > > + nb_streams = s->nb_streams;
> > > + mc = av_mallocz(sizeof(*mc));
> > > + if (!mc)
> > > + return AVERROR(ENOMEM);
> > > + stsd_ctx = avio_alloc_context(track->codec_priv.data,
> > > + track->codec_priv.size,
> > > + 0, NULL, NULL, NULL, NULL);
> > > + if (!stsd_ctx)
> > > + return AVERROR(ENOMEM);
> > I haven't looked at this patch deeply yet, but it seems to me that you
> > should rather use ffio_init_context like it is done in the code that
> > you intend to delete. That saves allocating and freeing stsd_ctx. You
> > can even reuse the AVIOContext b that already exists on the stack.
>
> Done.
>
> > > + mc->fc = s;
> > > + st->priv_data = msc = av_mallocz(sizeof(MOVStreamContext));
> > > + if (!msc) {
> > > + av_free(mc);
> > > + st->priv_data = priv_data;
> > > + return AVERROR(ENOMEM);
> > > }
> > > - if (codec_id == AV_CODEC_ID_NONE)
> > > - av_log(matroska->ctx, AV_LOG_ERROR,
> > > - "mov FourCC not found %s.\n", av_fourcc2str(fourcc));
> > > - if (track->codec_priv.size >= 86) {
> > > - bit_depth = AV_RB16(track->codec_priv.data + 82);
> > > - ffio_init_context(&b, track->codec_priv.data,
> > > - track->codec_priv.size,
> > > - 0, NULL, NULL, NULL, NULL);
> > > - if (ff_get_qtpalette(codec_id, &b, track->palette)) {
> > > - bit_depth &= 0x1F;
> > > - track->has_palette = 1;
> > Why are you removing this code? What about tracks that ought to have a
> > palette?
>
> The palette parsing is done in the stsd parser, but it still has to be
> copied back into the track,
> which is done in the later patch.
>
> > > - }
> > > + /* ff_mov_read_stsd_entries updates stream s->nb_streams-1,
> > > + * so set it temporarily to indicate which stream to update. */
> > > + s->nb_streams = st->index + 1;
> > > + ff_mov_read_stsd_entries(mc, stsd_ctx, 1);
> > > + av_free(msc);
> > > + av_free(mc);
> > > + avio_context_free(&stsd_ctx);
> > > + st->priv_data = priv_data;
> > > + s->nb_streams = nb_streams;
> > > +
> > > + // dvh1 in mkv is likely HEVC
> > > + if (st->codecpar->codec_tag == MKTAG('d','v','h','1')) {
> > > + codec_id = AV_CODEC_ID_HEVC;
> > > }
> > > } else if (codec_id == AV_CODEC_ID_PCM_S16BE) {
> > > switch (track->audio.bitdepth) {
> > >
> >
> > Also, your patch should refer to the exact component that is about to
> > be changed: avformat/matroskadec.
>
> Done.
>
> >
> > - Andreas
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> > To unsubscribe, visit link above, or email
> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
> matroskadec.c | 61 ++++++++++++++++++++++++++++++++++++++++------------------
> 1 file changed, 43 insertions(+), 18 deletions(-)
> 5dbf0d633a4567ad24eb07356d5de3c4a67b19e0 0001-avformat-matroskadec-properly-parse-stsd-in-v_quickt.patch
> From 18d1e18e3c72f70c2d9aaf2e8d9270a28b4895a2 Mon Sep 17 00:00:00 2001
> From: Stanislav Ionascu <stanislav.ionascu at gmail.com>
> Date: Sun, 11 Aug 2019 21:10:30 +0200
> Subject: [PATCH] avformat/matroskadec: properly parse stsd in v_quicktime
>
> Per matroska spec, v_quicktime contains the complete stsd atom, after
> the mandatory size + fourcc. By properly parsing the hvcc sub-atoms of
> the track, it becomes possible to demux/decode mp4/mov tracks stored as is
> in matroska containers.
>
> Also dvh1 in stsd in matroska is more likely hevc codec than dv.
> QuickTime palette parsing is reused from the stsd parser results.
>
> Signed-off-by: Stanislav Ionascu <stanislav.ionascu at gmail.com>
> ---
> libavformat/matroskadec.c | 61 +++++++++++++++++++++++++++------------
> 1 file changed, 43 insertions(+), 18 deletions(-)
breaks ./ffmpeg -i Earth\ Spin\ 1-bit\ qtrle.mkv -f null -
link to the file is in bf42a7ef6d073221915dcc042c080374045ab245 (and still works as of this writing)
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
The educated differ from the uneducated as much as the living from the
dead. -- Aristotle
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