On 01-10-2019 11:53 PM, James Almer wrote:
On 10/1/2019 3:11 PM, Gyan wrote:
On 01-10-2019 11:26 PM, Calvin Walton wrote:
The ffmpeg code read and wrote a 64bit duration field (in timebase
units) in the ivf
header, where the libvpx and chromium code instead use a 32bit frame
count field, and
then 32bits of unused (reserved?) space.
Switch ffmpeg to match the behaviour of libvpx & chromium.
Note that libvpx writes 0 to the frame count field when initially
writing the header
then seeks back and overwrites it with the real frame count. ffmpeg
used to write
0xFFFFFFFF - I've changed the behaviour to match libvpx.
References:
https://github.com/webmproject/libvpx/blob/v1.8.1/ivfenc.c#L16
Which is called from:
https://github.com/webmproject/libvpx/blob/v1.8.1/vpxenc.c#L1191
(initial header)
https://github.com/webmproject/libvpx/blob/v1.8.1/vpxenc.c#L1209
(rewrite with frame count)
And the chromium parser:
https://chromium.googlesource.com/chromium/src/media/+/1681b9abff73fe0e3d0932aefdab4f039a284d1a/filters/ivf_parser.h
---
libavformat/ivfdec.c | 3 ++-
libavformat/ivfenc.c | 11 ++++-------
2 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/libavformat/ivfdec.c b/libavformat/ivfdec.c
index 40ae464b76..2eaa5164ff 100644
--- a/libavformat/ivfdec.c
+++ b/libavformat/ivfdec.c
@@ -53,7 +53,8 @@ static int read_header(AVFormatContext *s)
st->codecpar->height = avio_rl16(s->pb);
time_base.den = avio_rl32(s->pb);
time_base.num = avio_rl32(s->pb);
- st->duration = avio_rl64(s->pb);
+ st->nb_frames = avio_rl32(s->pb);
+ avio_skip(s->pb, 4); // 32 bits unused
st->need_parsing = AVSTREAM_PARSE_HEADERS;
diff --git a/libavformat/ivfenc.c b/libavformat/ivfenc.c
index adf72117e9..85ca6045ba 100644
--- a/libavformat/ivfenc.c
+++ b/libavformat/ivfenc.c
@@ -22,8 +22,7 @@
#include "libavutil/intreadwrite.h"
typedef struct IVFEncContext {
- unsigned frame_cnt;
- uint64_t last_pts, sum_delta_pts;
+ uint32_t frame_cnt;
} IVFEncContext;
static int ivf_write_header(AVFormatContext *s)
@@ -53,7 +52,8 @@ static int ivf_write_header(AVFormatContext *s)
avio_wl16(pb, par->height);
avio_wl32(pb, s->streams[0]->time_base.den);
avio_wl32(pb, s->streams[0]->time_base.num);
- avio_wl64(pb, 0xFFFFFFFFFFFFFFFFULL);
+ avio_wl32(pb, 0); // frame count
+ avio_wl32(pb, 0); // unused
return 0;
}
@@ -66,10 +66,7 @@ static int ivf_write_packet(AVFormatContext *s,
AVPacket *pkt)
avio_wl32(pb, pkt->size);
avio_wl64(pb, pkt->pts);
avio_write(pb, pkt->data, pkt->size);
- if (ctx->frame_cnt)
- ctx->sum_delta_pts += pkt->pts - ctx->last_pts;
ctx->frame_cnt++;
- ctx->last_pts = pkt->pts;
return 0;
}
@@ -83,7 +80,7 @@ static int ivf_write_trailer(AVFormatContext *s)
size_t end = avio_tell(pb);
avio_seek(pb, 24, SEEK_SET);
- avio_wl64(pb, ctx->frame_cnt * ctx->sum_delta_pts /
(ctx->frame_cnt - 1));
+ avio_wl32(pb, ctx->frame_cnt);
avio_seek(pb, end, SEEK_SET);
}
See http://www.ffmpeg.org/pipermail/ffmpeg-devel/2019-October/250871.html
Gyan
That patch was already NAKed, and a fixed version sent in replacement.
I intended to link to the start of the thread, not the patch.
Gyan
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