[FFmpeg-user] FFv1: newer ffmpeg builds create larger files?

[Peter B.]

On 06/18/2012 04:32 PM, Paul B Mahol wrote:
> On 6/18/12, Peter B. <pb at das-werkstatt.com> wrote:
>> Quoting Michael Niedermayer <michaelni at gmx.at>:
>>
>>> On Mon, Jun 04, 2012 at 07:31:34PM +0200, Peter B. wrote:
>>>> On 06/04/2012 02:56 AM, Michael Niedermayer wrote:
>>>>> On Mon, Jun 04, 2012 at 01:22:27AM +0200, Peter B. wrote:
>>>>>> Hm... I don't see any information about the bitstream parameters.
>>>>>> I've tried 2 things with "-debug 1":
>>>>>> 1) calling ffprobe on the original
>>>>>> 2) transcoding the original as before
>>>>> [...]
>>>>>> Is there something I've misunderstood/overlooked?
>>>>> ffmpeg -debug 1 -i ffv1file -f null -
>>>>>
>>>> Thank you! Interesting commandline :)
>>>>
>>>> Interestingly, this showed "coder:0" for the original (=smallest) file,
>>>> whereas using "-coder 0" resulted in larger files than "-coder 1" in my
>>>> tests.
>>>>
>>>> When I checked files encoded with "-coder 1", the above command output
>>>> "coder:2" - I've verified this behavior, and all files encoded with
>>>> "-coder 1" are being shown with "-coder 2". Why is that?
>>> The difference between coder type 1 and 2 are documented in the spec
>>> coder type 2 performs better than 1 in all cases i remember
>>> so its used by default when range coding is requested
>> I think there's a misunderstanding here:
>> I thought that the valid values for "-coder" are "0" and "1", not "1"
>> and "2". Correct me if I'm wrong.
>>
>> Secondly, the puzzling part is, that the ffv1-files I'm getting from
>> the realtime encoding during capture (using ffdshow-tryouts with ffv1
>> version 1), are way smaller than *any* ffv1-encoded version of the
>> same content, transcoded with the current git-version(s) of ffmpeg.
>>
>> Why is it that I'm unable to reproduce these small files - regardless
>> which parameters I use?
> Are you sure that pixel formats are same in both files?
Absolutely.
Same resolution, same pix_fmt, same framerate.

Here's a copy of ffprobe's output on both, the original and its
transcoded version:

//-------------------------[Original]
Input #0, avi, from 'bsp-00001-100.avi':
  Metadata:
    IARL            : bsp-00001
    date            : 2012-03-11T02:49:06+01:00
    track           : 101 / 185
    encoder         : Lavf52.111.0
  Duration: 00:01:00.00, start: 0.000000, bitrate: 60324 kb/s
    Stream #0:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p, 720x576, 25
tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 2
channels, s16, 1536 kb/s


//-------------------------[Transcoded]
Input #0, avi, from 'bsp-00001-100-ffv1-yuv422p-l3_t8_s30-1_g01_c1_p2.avi':
  Metadata:
    IARL            : bsp-00001
    date            : 2012-03-11T02:49:06+01:00
    track           : 101 / 185
    encoder         : Lavf54.6.101
  Duration: 00:01:00.00, start: 0.000000, bitrate: 62267 kb/s
    Stream #0:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p, 720x576, SAR
16:15 DAR 4:3, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 2
channels, s16, 1536 kb/s

//-------------------------