[FFmpeg-cvslog] avformat/movenc: split MPEG-4 bit rate value calculation
Jan Ekström
git at videolan.org
Tue Sep 22 18:34:33 EEST 2020
ffmpeg | branch: master | Jan Ekström <jeebjp at gmail.com> | Sun Sep 20 14:41:18 2020 +0300| [667d5045d38c19a9a7ccfe7f1abaaf4cb8b225fc] | committer: Jan Ekström
avformat/movenc: split MPEG-4 bit rate value calculation
This can now be re-utilized in other places.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=667d5045d38c19a9a7ccfe7f1abaaf4cb8b225fc
---
libavformat/movenc.c | 44 ++++++++++++++++++++++++++++++++++----------
1 file changed, 34 insertions(+), 10 deletions(-)
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 12471c7d68..5888d10770 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -633,12 +633,41 @@ static unsigned compute_avg_bitrate(MOVTrack *track)
return size * 8 * track->timescale / track->track_duration;
}
+struct mpeg4_bit_rate_values {
+ uint32_t buffer_size; ///< Size of the decoding buffer for the elementary stream in bytes.
+ uint32_t max_bit_rate; ///< Maximum rate in bits/second over any window of one second.
+ uint32_t avg_bit_rate; ///< Average rate in bits/second over the entire presentation.
+};
+
+static struct mpeg4_bit_rate_values calculate_mpeg4_bit_rates(MOVTrack *track)
+{
+ AVCPBProperties *props =
+ (AVCPBProperties*)av_stream_get_side_data(track->st,
+ AV_PKT_DATA_CPB_PROPERTIES,
+ NULL);
+ struct mpeg4_bit_rate_values bit_rates = { 0 };
+
+ bit_rates.avg_bit_rate = compute_avg_bitrate(track);
+
+ // (FIXME should be max rate in any 1 sec window)
+ bit_rates.max_bit_rate = FFMAX(track->par->bit_rate,
+ bit_rates.avg_bit_rate);
+
+ // utilize values from properties if we have them available
+ if (props) {
+ bit_rates.max_bit_rate = FFMAX(bit_rates.max_bit_rate,
+ props->max_bitrate);
+ bit_rates.buffer_size = props->buffer_size / 8;
+ }
+
+ return bit_rates;
+}
+
static int mov_write_esds_tag(AVIOContext *pb, MOVTrack *track) // Basic
{
- AVCPBProperties *props;
+ struct mpeg4_bit_rate_values bit_rates = calculate_mpeg4_bit_rates(track);
int64_t pos = avio_tell(pb);
int decoder_specific_info_len = track->vos_len ? 5 + track->vos_len : 0;
- unsigned avg_bitrate;
avio_wb32(pb, 0); // size
ffio_wfourcc(pb, "esds");
@@ -669,14 +698,9 @@ static int mov_write_esds_tag(AVIOContext *pb, MOVTrack *track) // Basic
else
avio_w8(pb, 0x11); // flags (= Visualstream)
- props = (AVCPBProperties*)av_stream_get_side_data(track->st, AV_PKT_DATA_CPB_PROPERTIES,
- NULL);
-
- avio_wb24(pb, props ? props->buffer_size / 8 : 0); // Buffersize DB
-
- avg_bitrate = compute_avg_bitrate(track);
- avio_wb32(pb, props ? FFMAX3(props->max_bitrate, props->avg_bitrate, avg_bitrate) : FFMAX(track->par->bit_rate, avg_bitrate)); // maxbitrate (FIXME should be max rate in any 1 sec window)
- avio_wb32(pb, avg_bitrate);
+ avio_wb24(pb, bit_rates.buffer_size); // Buffersize DB
+ avio_wb32(pb, bit_rates.max_bit_rate); // maxbitrate
+ avio_wb32(pb, bit_rates.avg_bit_rate);
if (track->vos_len) {
// DecoderSpecific info descriptor
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