[FFmpeg-devel] [PATCH 1/2] avformat/nutenc: fix duration estimation by writing EOR packets
Paul B Mahol
onemda at gmail.com
Wed Dec 19 22:57:07 EET 2018
On 12/19/18, James Almer <jamrial at gmail.com> wrote:
> On 12/18/2018 10:56 AM, Paul B Mahol wrote:
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>> libavformat/nut.h | 3 +
>> libavformat/nutenc.c | 130 +++++++++++++++++++++++++++++++++++++++++--
>> 2 files changed, 129 insertions(+), 4 deletions(-)
>>
>> diff --git a/libavformat/nut.h b/libavformat/nut.h
>> index a4409ee23d..4b15dca1ea 100644
>> --- a/libavformat/nut.h
>> +++ b/libavformat/nut.h
>> @@ -76,6 +76,9 @@ typedef struct StreamContext {
>> int last_flags;
>> int skip_until_key_frame;
>> int64_t last_pts;
>> + int64_t eor_pts;
>> + int64_t eor_dts;
>> + int eor_flushed;
>> int time_base_id;
>> AVRational *time_base;
>> int msb_pts_shift;
>> diff --git a/libavformat/nutenc.c b/libavformat/nutenc.c
>> index e9a3bb49db..9d1c540a9d 100644
>> --- a/libavformat/nutenc.c
>> +++ b/libavformat/nutenc.c
>> @@ -940,6 +940,80 @@ fail:
>> return ret;
>> }
>>
>> +static void nut_update_max_pts(AVFormatContext *s, int stream_index,
>> int64_t pts)
>> +{
>> + NUTContext *nut = s->priv_data;
>> + StreamContext *nus = &nut->stream[stream_index];
>> +
>> + if (!nut->max_pts_tb || av_compare_ts(nut->max_pts, *nut->max_pts_tb,
>> pts, *nus->time_base) < 0) {
>> + nut->max_pts = pts;
>> + nut->max_pts_tb = nus->time_base;
>> + }
>> +}
>> +
>> +static int nut_write_eor(AVFormatContext *s, AVPacket *pkt)
>> +{
>> + AVIOContext *bc = s->pb, *dyn_bc;
>> + NUTContext *nut = s->priv_data;
>> + StreamContext *nus = &nut->stream[pkt->stream_index];
>> + int ret, frame_code, flags, needed_flags;
>> + int64_t pts = pkt->pts;
>> + int64_t coded_pts;
>> + FrameCode *fc;
>> +
>> + coded_pts = pts & ((1 << nus->msb_pts_shift) - 1);
>> + if (ff_lsb2full(nus, coded_pts) != pts)
>> + coded_pts = pts + (1 << nus->msb_pts_shift);
>> +
>> + nut->last_syncpoint_pos = avio_tell(bc);
>> + ret = avio_open_dyn_buf(&dyn_bc);
>> + if (ret < 0)
>> + return ret;
>> + put_tt(nut, nus->time_base, dyn_bc, pkt->dts);
>> + ff_put_v(dyn_bc, 0);
>> +
>> + if (nut->flags & NUT_BROADCAST) {
>> + put_tt(nut, nus->time_base, dyn_bc,
>> + av_rescale_q(av_gettime(), AV_TIME_BASE_Q,
>> *nus->time_base));
>> + }
>> + put_packet(nut, bc, dyn_bc, 1, SYNCPOINT_STARTCODE);
>> +
>> + frame_code = -1;
>> + for (int i = 0; i < 256; i++) {
>> + FrameCode *fc = &nut->frame_code[i];
>> + int flags = fc->flags;
>> +
>> + if (flags & FLAG_INVALID)
>> + continue;
>> +
>> + if (!(flags & FLAG_CODED)) {
>> + continue;
>> + }
>> +
>> + frame_code = i;
>> + break;
>> + }
>> + av_assert0(frame_code != -1);
>> +
>> + fc = &nut->frame_code[frame_code];
>> + flags = fc->flags;
>> + needed_flags = FLAG_KEY | FLAG_EOR | FLAG_CODED_PTS | FLAG_STREAM_ID;
>> +
>> + ffio_init_checksum(bc, ff_crc04C11DB7_update, 0);
>> + avio_w8(bc, frame_code);
>> + if (flags & FLAG_CODED) {
>> + ff_put_v(bc, (flags ^ needed_flags) & ~(FLAG_CODED));
>> + flags = needed_flags;
>> + }
>> + if (flags & FLAG_STREAM_ID) ff_put_v(bc, pkt->stream_index);
>> + if (flags & FLAG_CODED_PTS) ff_put_v(bc, coded_pts);
>> + ffio_get_checksum(bc);
>> +
>> + nut_update_max_pts(s, pkt->stream_index, pkt->pts);
>> +
>> + return 0;
>> +}
>> +
>> static int nut_write_packet(AVFormatContext *s, AVPacket *pkt)
>> {
>> NUTContext *nut = s->priv_data;
>> @@ -956,6 +1030,9 @@ static int nut_write_packet(AVFormatContext *s,
>> AVPacket *pkt)
>> int data_size = pkt->size;
>> uint8_t *sm_buf = NULL;
>>
>> + if (!data_size)
>> + return nut_write_eor(s, pkt);
>> +
>> if (pkt->pts < 0) {
>> av_log(s, AV_LOG_ERROR,
>> "Negative pts not supported stream %d, pts %"PRId64"\n",
>> @@ -1150,10 +1227,7 @@ static int nut_write_packet(AVFormatContext *s,
>> AVPacket *pkt)
>> nus->keyframe_pts[nut->sp_count] = pkt->pts;
>> }
>>
>> - if (!nut->max_pts_tb || av_compare_ts(nut->max_pts, *nut->max_pts_tb,
>> pkt->pts, *nus->time_base) < 0) {
>> - nut->max_pts = pkt->pts;
>> - nut->max_pts_tb = nus->time_base;
>> - }
>> + nut_update_max_pts(s, pkt->stream_index, pkt->pts);
>>
>> fail:
>> av_freep(&sm_buf);
>> @@ -1161,6 +1235,53 @@ fail:
>> return ret;
>> }
>>
>> +static int nut_interleave_packet(AVFormatContext *s, AVPacket *out,
>> + AVPacket *pkt, int flush)
>> +{
>> + NUTContext *nut = s->priv_data;
>> + int ret;
>> +
>> + if (pkt) {
>> + StreamContext *nus = &nut->stream[pkt->stream_index];
>> +
>> + nus->eor_pts = FFMAX(pkt->pts + pkt->duration, nus->eor_pts);
>> + nus->eor_dts = FFMAX(pkt->dts + pkt->duration, nus->eor_dts);
>> + } else if (flush) {
>> + StreamContext *nus;
>> + int i;
>> +
>> + for (i = 0; i < s->nb_streams; i++) {
>> + nus = &nut->stream[i];
>> +
>> + if (nus->eor_flushed)
>> + continue;
>> +
>> + if (s->streams[i]->last_in_packet_buffer)
>> + continue;
>> +
>> + break;
>> + }
>> +
>> + if (i < s->nb_streams) {
>> + pkt = av_packet_alloc();
>> + if (!pkt)
>> + return AVERROR(ENOMEM);
>> +
>> + ret = av_new_packet(pkt, 0);
>> + if (ret < 0)
>> + return ret;
>> + pkt->stream_index = i;
>> + pkt->pts = nus->eor_pts;
>> + pkt->dts = nus->eor_dts;
>> + pkt->duration = 0;
>> + nus->eor_flushed = 1;
>> + ret = ff_interleave_packet_per_dts(s, out, pkt, 0);
>
> This apparently will create a new reference for pkt, but will not unref
> the existing one or free the packet.
>
Are you sure? Do you have proof?
> The line below should be av_packet_free(&pkt) instead.
>
That will cause crash.
>> + pkt = NULL;
>> + }
>> + }
>> + return ff_interleave_packet_per_dts(s, out, pkt, flush);
>> +}
>> +
>> static int nut_write_trailer(AVFormatContext *s)
>> {
>> NUTContext *nut = s->priv_data;
>> @@ -1225,6 +1346,7 @@ AVOutputFormat ff_nut_muxer = {
>> .write_header = nut_write_header,
>> .write_packet = nut_write_packet,
>> .write_trailer = nut_write_trailer,
>> + .interleave_packet = nut_interleave_packet,
>> .deinit = nut_write_deinit,
>> .flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS,
>> .codec_tag = ff_nut_codec_tags,
>>
>
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