[FFmpeg-devel] [PATCH 1/2] avformat/movenc: fix sample size being zero in pcmC

[Raphaël Zumer]

On 7/25/23 23:45, Zhao Zhili wrote:
> From: Zhao Zhili <zhilizhao at tencent.com>
>
> -    avio_w8(pb, track->par->bits_per_raw_sample);
> +    sample_size = track->par->bits_per_raw_sample;
> +    if (!sample_size)
> +        sample_size = av_get_exact_bits_per_sample(track->par->codec_id);
> +    av_assert0(sample_size);
> +    avio_w8(pb, sample_size);

Why not just replace bits_per_raw_sample completely with av_get_exact_bits_per_sample()?

Are there edge cases, like incorrect codec ID, or sample sizes smaller than specified by the codec ID (and if there is ever a mismatch, which is expected in pcmC?)

If not, there should be no need to prioritize bits_per_raw_sample in the first place and add a fallback - going straight to av_get_exact_bits_per_sample() should suffice and keep the code simpler.

As noted in another thread, bits_per_raw_sample seems to always be 0 when muxing PCM to MP4 with FFmpeg, whereas bits_per_coded_sample has the correct value from the samples that I tested.

Raphaël Zumer