[FFmpeg-devel] avformat/mxfenc: SMPTE RDD 48:2018 Amd 1:2022 (FFV1 in MXF) support

[Jerome Martinez]

On 01/04/2023 16:37, Michael Niedermayer wrote:
> On Tue, Mar 14, 2023 at 10:52:15AM +0100, Jerome Martinez wrote:
> [...]
>> +
>> +    memset(state, 128, sizeof(state));
>> +    if (st->codecpar->extradata) {
>> +        ff_init_range_decoder(&c, st->codecpar->extradata, st->codecpar->extradata_size);
>> +        ff_build_rac_states(&c, 0.05 * (1LL << 32), 256 - 8);
>> +        v = get_ffv1_unsigned_symbol(&c, state);
>> +        av_assert0(v >= 2);
>> +        if (v > 4) {
>> +            return 0;
>> +        }
>> +        sc->micro_version = get_ffv1_unsigned_symbol(&c, state);
>> +    } else {
>> +        uint8_t keystate = 128;
>> +        ff_init_range_decoder(&c, pkt->data, pkt->size);
>> +        ff_build_rac_states(&c, 0.05 * (1LL << 32), 256 - 8);
>> +        get_rac(&c, &keystate); // keyframe
>> +        v = get_ffv1_unsigned_symbol(&c, state);
>> +        av_assert0(v < 2);
> Are these asserts testing muxer input ?
> if so what ensures that the values are within the asserted range ?


My understanding of the code and workflow is that the input is currently 
rejected (AV_LOG_ERROR, "invalid version %d in ver01 header\n" and 
AV_LOG_ERROR, "Invalid version in global header\n") in ffv1dec.c during 
the analysis of this input so before this piece of code is reached.
Could be an AV_LOG_ERROR if preferred.