Stefano Sabatini:
> Harmonize internal implementation with the mkvextract behavior:
> - print PTS in place of DTS values
> - ignore NOPTS values
> - sort PTS values
> ---
> libavformat/mkvtimestamp_v2.c | 69 +++++++++++++++++++++++++++++++++--
> 1 file changed, 65 insertions(+), 4 deletions(-)
>
> diff --git a/libavformat/mkvtimestamp_v2.c b/libavformat/mkvtimestamp_v2.c
> index 1eb2daf10a..c6446ed489 100644
> --- a/libavformat/mkvtimestamp_v2.c
> +++ b/libavformat/mkvtimestamp_v2.c
> @@ -22,30 +22,91 @@
> #include "avformat.h"
> #include "internal.h"
> #include "mux.h"
> +#include "libavutil/qsort.h"
> +
> +#define PTSS_MAX_SIZE 128
> +#define PTSS_HALF_SIZE (PTSS_MAX_SIZE >> 1)
> +
> +struct MkvTimestampContext {
> + int64_t ptss[PTSS_MAX_SIZE];
> + size_t ptss_size;
> +};
>
> static int write_header(AVFormatContext *s)
> {
> - static const char *header = "# timecode format v2\n";
> + static const char *header = "# timestamp format v2\n";
> avio_write(s->pb, header, strlen(header));
> avpriv_set_pts_info(s->streams[0], 64, 1, 1000);
> +
> return 0;
> }
>
> +static int cmp_int64(const void *p1, const void *p2)
> +{
> + int64_t left = *(const int64_t *)p1;
> + int64_t right = *(const int64_t *)p2;
> + return FFDIFFSIGN(left, right);
> +}
> +
> static int write_packet(AVFormatContext *s, AVPacket *pkt)
> {
> char buf[256];
> + int i;
> + struct MkvTimestampContext *m = s->priv_data;
> +
> if (pkt->stream_index)
> av_log(s, AV_LOG_WARNING, "More than one stream unsupported\n");
> - snprintf(buf, sizeof(buf), "%" PRId64 "\n", pkt->dts);
> - avio_write(s->pb, buf, strlen(buf));
> +
> + if (pkt->pts == AV_NOPTS_VALUE) {
> + av_log(s, AV_LOG_WARNING, "Found PTS with no value, ignored\n");
> + return 0;
> + }
> +
> + if (m->ptss_size > PTSS_MAX_SIZE) {
> + // sort all PTSs
> + AV_QSORT(m->ptss, PTSS_MAX_SIZE, int64_t, cmp_int64);
> +
> + // write only the first half and copy the second half to the
> + // beginning of the array
> + for (i = 0; i < PTSS_HALF_SIZE; i++) {
> + snprintf(buf, sizeof(buf), "%" PRId64 "\n", m->ptss[i]);
> + avio_write(s->pb, buf, strlen(buf));
> + m->ptss[i] = m->ptss[i + PTSS_HALF_SIZE];
> + }
> +
> + m->ptss_size = PTSS_HALF_SIZE;
> + } else {
> + m->ptss[m->ptss_size++] = pkt->pts;
> + }
> +
> + return 0;
> +}
> +
> +static int write_trailer(struct AVFormatContext *s)
> +{
> + struct MkvTimestampContext *m = s->priv_data;
> + char buf[256];
> + int i;
> +
> + // sort all PTSs
> + AV_QSORT(m->ptss, m->ptss_size, int64_t, cmp_int64);
> +
> + /* flush remaining timestamps */
> + for (i = 0; i < m->ptss_size; i++) {
> + snprintf(buf, sizeof(buf), "%" PRId64 "\n", m->ptss[i]);
> + avio_write(s->pb, buf, strlen(buf));
> + }
> +
> return 0;
> }
>
> const FFOutputFormat ff_mkvtimestamp_v2_muxer = {
> .p.name = "mkvtimestamp_v2",
> - .p.long_name = NULL_IF_CONFIG_SMALL("mkvtoolnix v2 timecode format"),
> + .p.long_name = NULL_IF_CONFIG_SMALL("mkvtoolnix v2 timestamp format"),
> .p.audio_codec = AV_CODEC_ID_NONE,
> .p.video_codec = AV_CODEC_ID_RAWVIDEO,
> .write_header = write_header,
> .write_packet = write_packet,
> + .write_trailer = write_trailer,
> + .priv_data_size = sizeof(struct MkvTimestampContext),
> };
1. This does not match mkvextract behaviour. mkvextract does not force a
1ms timebase.
2. AV_QSORT should only be used in speed-critical code, which this here
is definitely not.
3. I still don't think that this muxer should exist at all.
- Andreas
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