diff options
author | Sasi Inguva <isasi@google.com> | 2016-09-26 19:56:26 +0300 |
---|---|---|
committer | Michael Niedermayer <michael@niedermayer.cc> | 2016-09-29 03:25:41 +0300 |
commit | dba2db6c0e4a18b9b69b846650401bf3a1d5a019 (patch) | |
tree | 886d2717ed37b555f3f1d951e89f1e05a21ef02d /libavformat | |
parent | 7e0235bdb145cf7975bda240acb629991c4b7048 (diff) |
lavf/mov.c: Make audio timestamps strictly monotonically increasing inside an edit list.
Fixes gapless decoding. Adjust skip_samples field correctly in case of DISCARDed audio frames.
Signed-off-by: Sasi Inguva <isasi@google.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavformat')
-rw-r--r-- | libavformat/mov.c | 80 |
1 files changed, 69 insertions, 11 deletions
diff --git a/libavformat/mov.c b/libavformat/mov.c index b84d9c03fc..8b7bbf10d1 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -2856,6 +2856,21 @@ static int64_t add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, } /** + * Rewrite timestamps of index entries in the range [end_index - frame_duration_buffer_size, end_index) + * by subtracting end_ts successively by the amounts given in frame_duration_buffer. + */ +static void fix_index_entry_timestamps(AVStream* st, int end_index, int64_t end_ts, + int64_t* frame_duration_buffer, + int frame_duration_buffer_size) { + int i = 0; + av_assert0(end_index >= 0 && end_index <= st->nb_index_entries); + for (i = 0; i < frame_duration_buffer_size; i++) { + end_ts -= frame_duration_buffer[frame_duration_buffer_size - 1 - i]; + st->index_entries[end_index - 1 - i].timestamp = end_ts; + } +} + +/** * Append a new ctts entry to ctts_data. * Returns the new ctts_count if successful, else returns -1. */ @@ -2919,7 +2934,10 @@ static void mov_fix_index(MOVContext *mov, AVStream *st) int64_t edit_list_media_time_dts = 0; int64_t edit_list_start_encountered = 0; int64_t search_timestamp = 0; - + int64_t* frame_duration_buffer = NULL; + int num_discarded_begin = 0; + int first_non_zero_audio_edit = -1; + int packet_skip_samples = 0; if (!msc->elst_data || msc->elst_count <= 0) { return; @@ -2955,6 +2973,7 @@ static void mov_fix_index(MOVContext *mov, AVStream *st) edit_list_index++; edit_list_dts_counter = edit_list_dts_entry_end; edit_list_dts_entry_end += edit_list_duration; + num_discarded_begin = 0; if (edit_list_media_time == -1) { continue; } @@ -2962,7 +2981,14 @@ static void mov_fix_index(MOVContext *mov, AVStream *st) // If we encounter a non-negative edit list reset the skip_samples/start_pad fields and set them // according to the edit list below. if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) { - st->skip_samples = msc->start_pad = 0; + if (first_non_zero_audio_edit < 0) { + first_non_zero_audio_edit = 1; + } else { + first_non_zero_audio_edit = 0; + } + + if (first_non_zero_audio_edit > 0) + st->skip_samples = msc->start_pad = 0; } //find closest previous key frame @@ -3041,24 +3067,56 @@ static void mov_fix_index(MOVContext *mov, AVStream *st) } if (curr_cts < edit_list_media_time || curr_cts >= (edit_list_duration + edit_list_media_time)) { - if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && curr_cts < edit_list_media_time && - curr_cts + frame_duration > edit_list_media_time && - st->skip_samples == 0 && msc->start_pad == 0) { - st->skip_samples = msc->start_pad = edit_list_media_time - curr_cts; - - // Shift the index entry timestamp by skip_samples to be correct. - edit_list_dts_counter -= st->skip_samples; + if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && st->codecpar->codec_id != AV_CODEC_ID_VORBIS && + curr_cts < edit_list_media_time && curr_cts + frame_duration > edit_list_media_time && + first_non_zero_audio_edit > 0) { + packet_skip_samples = edit_list_media_time - curr_cts; + st->skip_samples += packet_skip_samples; + + // Shift the index entry timestamp by packet_skip_samples to be correct. + edit_list_dts_counter -= packet_skip_samples; if (edit_list_start_encountered == 0) { - edit_list_start_encountered = 1; + edit_list_start_encountered = 1; + // Make timestamps strictly monotonically increasing for audio, by rewriting timestamps for + // discarded packets. + if (frame_duration_buffer) { + fix_index_entry_timestamps(st, st->nb_index_entries, edit_list_dts_counter, + frame_duration_buffer, num_discarded_begin); + av_freep(&frame_duration_buffer); + } } - av_log(mov->fc, AV_LOG_DEBUG, "skip %d audio samples from curr_cts: %"PRId64"\n", st->skip_samples, curr_cts); + av_log(mov->fc, AV_LOG_DEBUG, "skip %d audio samples from curr_cts: %"PRId64"\n", packet_skip_samples, curr_cts); } else { flags |= AVINDEX_DISCARD_FRAME; av_log(mov->fc, AV_LOG_DEBUG, "drop a frame at curr_cts: %"PRId64" @ %"PRId64"\n", curr_cts, index); + + if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && edit_list_start_encountered == 0) { + num_discarded_begin++; + frame_duration_buffer = av_realloc(frame_duration_buffer, + num_discarded_begin * sizeof(int64_t)); + if (!frame_duration_buffer) { + av_log(mov->fc, AV_LOG_ERROR, "Cannot reallocate frame duration buffer\n"); + break; + } + frame_duration_buffer[num_discarded_begin - 1] = frame_duration; + + // Increment skip_samples for the first non-zero audio edit list + if (first_non_zero_audio_edit > 0 && st->codecpar->codec_id != AV_CODEC_ID_VORBIS) { + st->skip_samples += frame_duration; + msc->start_pad = st->skip_samples; + } + } } } else if (edit_list_start_encountered == 0) { edit_list_start_encountered = 1; + // Make timestamps strictly monotonically increasing for audio, by rewriting timestamps for + // discarded packets. + if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && frame_duration_buffer) { + fix_index_entry_timestamps(st, st->nb_index_entries, edit_list_dts_counter, + frame_duration_buffer, num_discarded_begin); + av_freep(&frame_duration_buffer); + } } if (add_index_entry(st, current->pos, edit_list_dts_counter, current->size, |