[FFmpeg-devel] FFV1.3

[Dave Rice]

Hi,

On Apr 20, 2012, at 9:50 AM, Michael Niedermayer wrote:

> Hi
> 
> Ive just commited some changes to the ffv1 codec v1.3

I downloaded from git-master and changed line 900 of ffv1.c to "    s->version=3;" in order to start some testing. So far I haven't gotten any files to encode and have been getting an error on the slice number regarding of the source content. Here's an example output using testsrc as an input.

 ./ffmpeg -y -t 5 -f lavfi -i testsrc -c:v ffv1 -strict experimental testsrc_ffv1.mov 
ffmpeg version N-40099-g2b336df Copyright (c) 2000-2012 the FFmpeg developers
  built on Apr 24 2012 17:20:15 with llvm_gcc 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)
  configuration: --enable-gpl
  libavutil      51. 47.100 / 51. 47.100
  libavcodec     54. 15.100 / 54. 15.100
  libavformat    54.  3.100 / 54.  3.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 72.100 /  2. 72.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 11.100 /  0. 11.100
  libpostproc    52.  0.100 / 52.  0.100
[testsrc @ 0x7f9843418440] size:320x240 rate:25/1 duration:-1.000000 sar:1/1
Input #0, lavfi, from 'testsrc':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 320x240 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
[buffer @ 0x7f98434197c0] w:320 h:240 pixfmt:rgb24 tb:1/1000000 sar:1/1 sws_param:flags=2
[buffersink @ 0x7f9843419a80] auto-inserting filter 'auto-inserted scale 0' between the filter 'src' and the filter 'out'
[scale @ 0x7f9843419fa0] w:320 h:240 fmt:rgb24 sar:1/1 -> w:320 h:240 fmt:bgr0 sar:1/1 flags:0x4
[ffv1 @ 0x7f9843850a00] Unsupported number 0 of slices requested
Output #0, mov, to 'testsrc_ffv1.mov':
    Stream #0:0: Video: ffv1, bgr0, 320x240 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo -> ffv1)
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

Dave Rice

> Whats new:
> 
> mandatory CRC on the global header
> 
> optional CRC on slices (The optionality is for discussion, we can make
> it mandatory if theres consens that this would be better, it would
> slow the encoder down a bit, bitrate wise it probably is negligible)
> 
> many fields have been moved from the frame header to the slice header,
> this is needed so one slice can be decoded when the others are damaged
> or lost
> 
> aspect ratio, top field first and interlace fields added, these could
> be droped again but i think they are better in ffv1 than the container
> because not all containers have these fields and thouse which do
> cant always change them mid file while mixed progressive/interlaced
> content exists and we want to support losslessly preserving it
> 
> Comments welcome
> 
> -- 
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> 
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