Hi Georg
Thanks for that, I'd somehow managed to overlook the -p flag in the
transcode manual page, and hadn't worked out the significance of the -N
audio format flags. In fact, however, transcode doesn't seem to directly
support the audio format I need (0x11 for imaadpcm). However, it turned
out that ffmpeg would remux the audio without reencoding it, so the
following sequence works...
DIR=.
BASENAME=somexvid
# extract the video, resize and encode
transcode -i $DIR/$BASENAME.avi -o ${BASENAME}_mjpeg.avi \
-x ffmpeg,null -Z 320x240 -y ffmpeg,null -F mjpeg
# extract the audio, resample to mono at 22050
transcode -i $DIR/$BASENAME.avi -o ${BASENAME}_pcm.wav \
-x null,mp3 -y null,wav -a 1 -E 22050,0,1 -Jresample
# re-encode audio to ima_adpcm
sox ${BASENAME}_pcm.wav -i ${BASENAME}_ima_adpcm.wav
# remux
ffmpeg -vcodec copy -i ${BASENAME}_mjpeg.avi \
-acodec copy -i ${BASENAME}_ima_adpcm.wav \
${BASENAME}_mjpeg_ima_adpcm.avi
...and the resulting files play on the camera (A casio exilim ex-z500)!
cheers
guy
Georg Martius wrote:
Hi Guy,
AFAIK you can do
transcode -i somexvidfile.avi -p camfile_imaadpcm.wav -o camfile.avi -Z
320x240 -y ffmpeg,raw -F mjpeg
and maybe a -N 0x01 additionally.
BTW: the cameras from cannon and panasonic I had so far used only 8000 kHz.
Hope it helped!
Georg
On Monday 30 March 2009, Guy Hindell wrote:
Hi there --- I guess this is a somewhat academic question, but...
Can anyone tell me if and how transcode (perhaps via ffmpeg, avimerge
etc.) can *encode* AVI files as mjpeg video with ima_adpcm audio? Why do
I want to do this? Well, I'm curious to see whether I can create files
in the same format as those produced by a Casio Exilim digital camera
such that they can be copied to the SD card and the camera will play them.
So far I can create files whose video content does play on the camera...
transcode -i somexvidfile.avi -o camfile.avi -Z 320x240 -y ffmpeg -F mjpeg
but whose audio is still the mp3 encoded 2 channel 44100Hz of the
original. The target audio is (I think) 1 channel 22050Hz encoded as
ima-adpcm. I've not been able to figure out how I can get ffmpeg to
create such audio, or how I can get transcode to use ffmpeg to do it
even if it could. However, the audio can be extracted like this...
trasncode -i somexvidfile.avi -o camfile_pcm.wav -E 22050,0,1 -x
null,raw -y wav
and sox used to convert from pcm to ima_adpcm...
sox camfile_pcm.wav -i camfile_imaadpcm.wav
and an avi with video but no sound is easy enough to create.
But... that's as far as I've got --- can transcode create an AVI that
combines my camfile.avi and camfile_imaadpcm.wav?
cheers
guy
