[Ffmpeg-devel] truncated audio output

[Michael Niedermayer]

Hi

On Mon, Jun 19, 2006 at 12:11:26AM -0400, Justin Ruggles wrote:
> After re-reading my post, I figured that my idea might be better
> explained by a patch.  Here is what it would look like if I modified the
> pcm encoder to use my suggestion instead of frame_size=1, which is what
> is used currently.

i agree that a CODEC_CAP_VAR_FRAME_SIZE needs to be added ...


[...]
> Index: ffmpeg/ffmpeg.c
> ===================================================================
> --- ffmpeg/ffmpeg.c	(.../svn://svn.mplayerhq.hu/ffmpeg/trunk)	(revision 5497)
> +++ ffmpeg/ffmpeg.c	(.../ffmpeg)	(working copy)
> @@ -526,7 +526,7 @@
>      }
>  
>      /* now encode as many frames as possible */
> -    if (enc->frame_size > 1) {
> +
>          /* output resampled raw samples */
>          fifo_write(&ost->fifo, buftmp, size_out,
>                     &ost->fifo.wptr);
> @@ -551,48 +551,6 @@
>  
>              ost->sync_opts += enc->frame_size;
>          }
> -    } else {
> -        AVPacket pkt;

i think we shouldnt drop support for leaving the packet size equal to
the input where its supported, that said i dont mind changing the default
to a fixed size if theres some advantage


[...]
> @@ -1357,12 +1315,32 @@
>                  if (ost->encoding_needed) {
>                      for(;;) {
>                          AVPacket pkt;
> +                        int fifo_bytes;
>                          av_init_packet(&pkt);
>                          pkt.stream_index= ost->index;
>  
>                          switch(ost->st->codec->codec_type) {
>                          case CODEC_TYPE_AUDIO:
> -                            ret = avcodec_encode_audio(enc, bit_buffer, bit_buffer_size, NULL);
> +                            fifo_bytes = fifo_size(&ost->fifo, NULL);
> +                            ret = 0;
> +                            /* encode any samples remaining in fifo */
> +                            if(fifo_bytes > 0 && enc->codec->capabilities & CODEC_CAP_VAR_FRAME_SIZE) {
> +                                int fs_tmp = enc->frame_size;
> +                                enc->frame_size = fifo_bytes / (2 * enc->channels);
> +                                if(enc->frame_size > fs_tmp) {
> +                                    enc->frame_size = fs_tmp;
> +                                }

why is that check needed? if we had more data then frame_size shouldnt that
have been encoded already? and what about non 16bit PCM?

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is