diff options
Diffstat (limited to '')
| -rw-r--r-- | src/decoder/plugins/FfmpegDecoderPlugin.cxx | 53 |
1 files changed, 48 insertions, 5 deletions
diff --git a/src/decoder/plugins/FfmpegDecoderPlugin.cxx b/src/decoder/plugins/FfmpegDecoderPlugin.cxx index f5c0e0a36..d5191a3c3 100644 --- a/src/decoder/plugins/FfmpegDecoderPlugin.cxx +++ b/src/decoder/plugins/FfmpegDecoderPlugin.cxx @@ -321,18 +321,44 @@ StreamRelativePts(const AVPacket &packet, const AVStream &stream) return pts - start; } +/** + * Convert a non-negative stream-relative time stamp in + * AVStream::time_base units to a PCM frame number. + */ +gcc_pure +static uint64_t +PtsToPcmFrame(uint64_t pts, const AVStream &stream, + const AVCodecContext &codec_context) +{ + return av_rescale_q(pts, stream.time_base, codec_context.time_base); +} + +/** + * @param min_frame skip all data before this PCM frame number; this + * is used after seeking to skip data in an AVPacket until the exact + * desired time stamp has been reached + */ static DecoderCommand ffmpeg_send_packet(Decoder &decoder, InputStream &is, const AVPacket *packet, AVCodecContext *codec_context, const AVStream *stream, AVFrame *frame, + uint64_t min_frame, size_t pcm_frame_size, uint8_t **buffer, int *buffer_size) { + size_t skip_bytes = 0; + const auto pts = StreamRelativePts(*packet, *stream); if (pts >= 0) { - decoder_timestamp(decoder, - time_from_ffmpeg(pts, stream->time_base)); + if (min_frame > 0) { + auto cur_frame = PtsToPcmFrame(pts, *stream, + *codec_context); + if (cur_frame < min_frame) + skip_bytes = pcm_frame_size * (min_frame - cur_frame); + } else + decoder_timestamp(decoder, + time_from_ffmpeg(pts, stream->time_base)); } AVPacket packet2 = *packet; @@ -368,8 +394,20 @@ ffmpeg_send_packet(Decoder &decoder, InputStream &is, if (audio_size <= 0) continue; + const uint8_t *data = output_buffer; + if (skip_bytes > 0) { + if (skip_bytes >= size_t(audio_size)) { + skip_bytes -= audio_size; + continue; + } + + data += skip_bytes; + audio_size -= skip_bytes; + skip_bytes = 0; + } + cmd = decoder_data(decoder, is, - output_buffer, audio_size, + data, audio_size, codec_context->bit_rate / 1000); } return cmd; @@ -573,6 +611,8 @@ ffmpeg_decode(Decoder &decoder, InputStream &input) uint8_t *interleaved_buffer = nullptr; int interleaved_buffer_size = 0; + uint64_t min_frame = 0; + DecoderCommand cmd; do { AVPacket packet; @@ -580,13 +620,15 @@ ffmpeg_decode(Decoder &decoder, InputStream &input) /* end of file */ break; - if (packet.stream_index == audio_stream) + if (packet.stream_index == audio_stream) { cmd = ffmpeg_send_packet(decoder, input, &packet, codec_context, av_stream, frame, + min_frame, audio_format.GetFrameSize(), &interleaved_buffer, &interleaved_buffer_size); - else + min_frame = 0; + } else cmd = decoder_get_command(decoder); av_free_packet(&packet); @@ -606,6 +648,7 @@ ffmpeg_decode(Decoder &decoder, InputStream &input) decoder_seek_error(decoder); else { avcodec_flush_buffers(codec_context); + min_frame = decoder_seek_where_frame(decoder); decoder_command_finished(decoder); } } |