[FFmpeg-user] AVC3 -> AVC1 conversion

[antony baxter]

Hello,

I've recently received some H264 videos marked as AVC3:

  Duration: 00:29:00.00, start: 0.000000, bitrate: 949 kb/s
    Stream #0:0(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz,
stereo, fltp, 125 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
    Stream #0:1(und): Video: h264 (Main) (avc3 / 0x33637661), yuvj420p(pc,
bt709), 704x396 [SAR 1:1 DAR 16:9], 819 kb/s, 25 fps, 25 tbr, 25k tbn, 50
tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:2: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown),
192x108 [SAR 72:72 DAR 16:9], 90k tbr, 90k tbn, 90k tbc

These are not natively playable by quicktime/iTunes under OSX High Sierra
(10.13.1).

I can obviously convert them into H264 avc1 the long way, but wondered if
there was a quick way of simply changing the metadata of the avc3 stream
into avc1?

I've tried splitting the audio and video into two streams, and then
remuxing. This worked, but the video was "jerky" and unwatchable.

Thanks for your help.

Ant.