ffmpeg for android，解码时内存不足，使用openh264旋转mp4文件

Question

Version

• ffmpeg : 4.0.2
• openh264: 1.8.0

Problem

I try to trim a .mp4 file which metadata info contains rotate info, but I failed with the error information.

The file stream info :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2018-10-09T09:40:53.000000Z
    location        : +39.8983+116.4145/
    location-eng    : +39.8983+116.4145/
    com.android.version: 6.0
  Duration: 00:00:10.56, start: 0.000000, bitrate: 8671 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 8563 kb/s, SAR 1:1 DAR 16:9, 30.01 fps, 30 tbr, 90k tbn, 180k tbc (default)
    Metadata:
      rotate          : 180
      creation_time   : 2018-10-09T09:40:53.000000Z
      handler_name    : VideoHandle
    Side data:
      displaymatrix: rotation of -180.00 degrees
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      creation_time   : 2018-10-09T09:40:53.000000Z
      handler_name    : SoundHandle

ffmpeg cmd

ffmpeg -y -i 1.mp4 -threads 4 -b:v 2000k -vcodec libopenh264 -acodec copy -ss 0 -t 3 -f mp4 -movflags faststart -strict -2 ./output.mp4

result

Error reinitializing filters!
Failed to inject frame into filter network: Out of memory
Error while processing the decoded data for stream #0:0

Then I found this answer: ffmpeg-for-android-out-of-memory , after i added -noautorotate command to my cmd, the video is trimmed successful.

If I use -vcodec copy instead of -vcodec libopenh264 , the result also is ok, I wonder if there is a bug when libopenh264 decode with ffmpeg's autorotate function.

I wipe the video's rotate info from metadata with -metadata:s:v:0 command, the newly video can be trimmed successful with the origin cmd :(

Answer 1

The error message is misleading. Due to your usage of --disable-filters you need to manually enable the hflip/vflip filters:

--enable-filter=aresample,crop,hflip,scale,transpose,vflip

Some filters (such as the format filter) will be automatically enabled in this case.