On Mon, Nov 20, 2017 at 08:27:05PM -0800, Sasi Inguva wrote:
> Signed-off-by: Sasi Inguva <is...@google.com>
> ---
> libavformat/mov.c | 50
> ++++++++++++++++++++++++++++++++++++++++
> tests/fate/mov.mak | 7 ++++++
> tests/ref/fate/mov-guess-delay-1 | 3 +++
> tests/ref/fate/mov-guess-delay-2 | 3 +++
> tests/ref/fate/mov-guess-delay-3 | 3 +++
> 5 files changed, 66 insertions(+)
> create mode 100644 tests/ref/fate/mov-guess-delay-1
> create mode 100644 tests/ref/fate/mov-guess-delay-2
> create mode 100644 tests/ref/fate/mov-guess-delay-3
>
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index fd170baa57..afb0d4ca5c 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -3213,6 +3213,54 @@ static int64_t add_ctts_entry(MOVStts** ctts_data,
> unsigned int* ctts_count, uns
> return *ctts_count;
> }
>
> +static void mov_guess_video_delay(MOVContext *c, AVStream* st) {
> + MOVStreamContext *msc = st->priv_data;
> + int ind;
> + int ctts_ind = 0;
> + int ctts_sample = 0;
> + int64_t curr_pts = AV_NOPTS_VALUE;
> + int64_t min_prev_pts = AV_NOPTS_VALUE;
> + int64_t prev_max_pts = AV_NOPTS_VALUE;
> + int num_steps = 0;
> +
> + if (st->codecpar->video_delay <= 0 && msc->ctts_data &&
> + st->codecpar->codec_id == AV_CODEC_ID_H264) {
> + st->codecpar->video_delay = 0;
> + for(ind = 0; ind < st->nb_index_entries && ctts_ind <
> msc->ctts_count; ++ind) {
> + curr_pts = st->index_entries[ind].timestamp +
> msc->ctts_data[ctts_ind].duration;
> +
> + // Everytime we encounter a new max_pts we reset num_steps and
> compute again.
> + if (curr_pts > prev_max_pts) {
> + st->codecpar->video_delay =
> FFMIN(FFMAX(st->codecpar->video_delay, num_steps), 16);
> + num_steps = 0;
> + prev_max_pts = curr_pts;
> + min_prev_pts = curr_pts;
> + } else {
> + // Compute delay as the length of the path from max PTS to
> min PTS.
> + // Frames: I0 I1 B0 B1 B2
> + // PTS: 0 4 1 2 3 -> num_steps = delay = 1 (4->1)
> + //
> + // Frames: I0 I1 B1 B0 B2
> + // PTS: 0 4 2 1 3 -> num_steps = delay = 2 (4->2,
> 2->1)
> + if (min_prev_pts != AV_NOPTS_VALUE) {
> + if (curr_pts < min_prev_pts) {
> + ++num_steps;
> + min_prev_pts = curr_pts;
> + }
> + }
> + }Can you explain why this algorithm is correct ? (iam asking as i suspect it is not correct, but i may be wrong) What this should do is find the minimum buffer size to sort the stream of frame timestamps. [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Its not that you shouldnt use gotos but rather that you should write readable code and code with gotos often but not always is less readable
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