Is -an redundant in image sequence to video recipe?

[kieranjol]

In this example, there is no audio in the input, so is -an necessary? I think it could be removed.

[privatezero]

That sounds right to me!

[retokromer]

I will test this when back from Sicily. If I remember carefully there where situations in which an empty sound track was added when -an was not specified.

[kieranjol]

Ah, I don't think I ever noticed this, I wonder if this involved the dv Codec?

On 13 Jul 2017 06:59, "Reto Kromer" notifications@github.com wrote:

I will test this when back from Sicily. If I remember carefully there where situations in which an empty sound track was added when -an was not specified.

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[kfrn]

I'd be interested to know what codecs/containers/combinations generated an empty soundtrack.

[retokromer]

I did extensive tests five years ago or so, and this happened in many configurations. I have to run the tests again, because some has been changed since… I will report back at the end of July.

[ablwr]

+1 @retokromer, I also can't test right now but I do think I ran into that situation as well, which is why we are being explicit in request for no audio.

[retokromer]

I tested that for single images -an is not needed with version 3.3.2.

[kieranjol]

Hi, in a very nerdy moment, possibly my nerdiest, I wrote a script that checks what video encoders are present in your ffmpeg build and transcodes a test dpx file to each codec and checks if there is an audio track present. A lot of the codecs fail due to incompatibilities with pix_fmts or matroska, but I confirm that I got zero audio tracks with matroska or mov. Here's the script: https://gist.github.com/kieranjol/77bc5985c7e8fcb4ff44af52f1572688 and here's the results, errors and all:

alias_pix cant read
None
amv 0
[matroska,webm @ 0x262b080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/apng.mkv: End of file
apng cant read
None
asv1 0
asv2 0
avrp 0
[matroska,webm @ 0x1b70080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/avui.mkv: Invalid data found when processing input
avui cant read
None
ayuv 0
[matroska,webm @ 0x1897080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/bmp.mkv: End of file
bmp cant read
None
cinepak 0
cljr 0
dirac 0
[matroska,webm @ 0xed1080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/dnxhd.mkv: Invalid data found when processing input
dnxhd cant read
None
dpx 0
[matroska,webm @ 0xb10080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/dvvideo.mkv: Invalid data found when processing input
dvvideo cant read
None
ffv1 0
ffvhuff 0
flashsv 0
[matroska,webm @ 0x6ee080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/flashsv2.mkv: End of file
flashsv2 cant read
None
flv1 0
gif 0
[matroska,webm @ 0xac1080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/h261.mkv: Invalid data found when processing input
h261 cant read
None
[matroska,webm @ 0xd44080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/h263.mkv: Invalid data found when processing input
h263 cant read
None
h263p 0
h264 0
x265 [info]: HEVC encoder version 2.4
x265 [info]: build info [Linux][GCC 4.8.4][64 bit] 8bit
x265 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
x265 [info]: Main 4:4:4 profile, Level-2 (Main tier)
x265 [info]: Thread pool created using 4 threads
x265 [info]: Slices                              : 1
x265 [info]: frame threads / pool features       : 2 / wpp(4 rows)
x265 [warning]: Source height < 720p; disabling lookahead-slices
x265 [info]: Coding QT: max CU size, min CU size : 64 / 8
x265 [info]: Residual QT: max TU size, max depth : 32 / 1 inter / 1 intra
x265 [info]: ME / range / subpel / merge         : hex / 57 / 2 / 2
x265 [info]: Keyframe min / max / scenecut / bias: 25 / 250 / 40 / 5.00
x265 [info]: Cb/Cr QP Offset                     : 6 / 6
x265 [info]: Lookahead / bframes / badapt        : 20 / 4 / 2
x265 [info]: b-pyramid / weightp / weightb       : 1 / 1 / 0
x265 [info]: References / ref-limit  cu / depth  : 3 / on / on
x265 [info]: AQ: mode / str / qg-size / cu-tree  : 1 / 1.0 / 32 / 1
x265 [info]: Rate Control / qCompress            : CRF-28.0 / 0.60
x265 [info]: tools: rd=3 psy-rd=2.00 rskip signhide tmvp strong-intra-smoothing
x265 [info]: tools: deblock sao
x265 [info]: frame I:      1, Avg QP:32.79  kb/s: 434.20  
x265 [info]: consecutive B-frames: 100.0% 0.0% 0.0% 0.0% 0.0% 

encoded 1 frames in 0.19s (5.40 fps), 434.20 kb/s, Avg QP:32.79
hevc 0
huffyuv 0
jpeg2000 0
jpegls 0
mjpeg 0
mpeg1video 0
mpeg2video 0
mpeg4 0
msmpeg4v2 0
msmpeg4v3 0
msvideo1 0
[matroska,webm @ 0x234f080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/pam.mkv: End of file
pam cant read
None
[matroska,webm @ 0x12ee080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/pbm.mkv: End of file
pbm cant read
None
[matroska,webm @ 0x12b4080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/pcx.mkv: End of file
pcx cant read
None
[matroska,webm @ 0x239f080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/pgm.mkv: End of file
pgm cant read
None
[matroska,webm @ 0x159a080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/pgmyuv.mkv: End of file
pgmyuv cant read
None
png 0
[matroska,webm @ 0x89e080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/ppm.mkv: End of file
ppm cant read
None
prores 0
[qtrle @ 0x1675b80] Unsupported colorspace: 0 bits/sample?
    Last message repeated 1 times
[qtrle @ 0x1676680] Unsupported colorspace: 0 bits/sample?
qtrle cant read
None
r10k 0
r210 0
[matroska,webm @ 0xe27080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/rawvideo.mkv: End of file
rawvideo cant read
None
[matroska,webm @ 0x1563080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/roq.mkv: End of file
roq cant read
None
[matroska,webm @ 0x185d080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/rv10.mkv: Invalid data found when processing input
rv10 cant read
None
[matroska,webm @ 0x68b080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/rv20.mkv: Invalid data found when processing input
rv20 cant read
None
sgi 0
snow 0
[matroska,webm @ 0x12ed080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/sunrast.mkv: End of file
sunrast cant read
None
svq1 0
targa 0
tiff 0
utvideo 0
v210 0
v308 0
v408 0
v410 0
wmv1 0
wmv2 0
[matroska,webm @ 0x237a080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/xbm.mkv: End of file
xbm cant read
None
[matroska,webm @ 0x1402080] EBML header parsing failed
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/xface.mkv: Invalid data found when processing input
xface cant read
None
[matroska,webm @ 0x14b0080] Duplicate element
    Last message repeated 1 times
/home/kieranjol/ifigit/ifiscripts/test_files_dpx/xwd.mkv: End of file
xwd cant read
None
y41p 0
yuv4 0
zlib 0
zmbv 0