[FFmpeg-devel] [PATCH v2 2/7] avformat/apm: prepare extradata handling for muxer
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Thu Jun 11 05:12:46 EEST 2020
Zane van Iperen:
> Signed-off-by: Zane van Iperen <zane at zanevaniperen.com>
> ---
> libavformat/Makefile | 2 +-
> libavformat/apm.c | 130 +++++++++++++++++++++++--------------------
> 2 files changed, 70 insertions(+), 62 deletions(-)
>
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 0658fa3710..bb09dc6563 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -93,7 +93,7 @@ OBJS-$(CONFIG_AMRWB_DEMUXER) += amr.o
> OBJS-$(CONFIG_ANM_DEMUXER) += anm.o
> OBJS-$(CONFIG_APC_DEMUXER) += apc.o
> OBJS-$(CONFIG_APE_DEMUXER) += ape.o apetag.o img2.o
> -OBJS-$(CONFIG_APM_DEMUXER) += apm.o riffdec.o
> +OBJS-$(CONFIG_APM_DEMUXER) += apm.o
> OBJS-$(CONFIG_APNG_DEMUXER) += apngdec.o
> OBJS-$(CONFIG_APNG_MUXER) += apngenc.o
> OBJS-$(CONFIG_APTX_DEMUXER) += aptxdec.o rawdec.o
> diff --git a/libavformat/apm.c b/libavformat/apm.c
> index dc59c16562..57d23200b0 100644
> --- a/libavformat/apm.c
> +++ b/libavformat/apm.c
> @@ -21,12 +21,13 @@
> */
> #include "avformat.h"
> #include "internal.h"
> -#include "riff.h"
> #include "libavutil/internal.h"
> #include "libavutil/intreadwrite.h"
>
> -#define APM_FILE_HEADER_SIZE 20
> -#define APM_VS12_CHUNK_SIZE 76
> +#define APM_FILE_HEADER_SIZE 18
> +#define APM_FILE_EXTRADATA_SIZE 80
> +#define APM_EXTRADATA_SIZE 28
> +
> #define APM_MAX_READ_SIZE 4096
>
> #define APM_TAG_CODEC 0x2000
> @@ -43,34 +44,37 @@ typedef struct APMState {
> int32_t saved_l;
> } APMState;
>
> -typedef struct APMVS12Chunk {
> +typedef struct APMExtraData {
> uint32_t magic;
> uint32_t file_size;
> uint32_t data_size;
> uint32_t unk1;
> uint32_t unk2;
> APMState state;
> - uint32_t pad[7];
> -} APMVS12Chunk;
> + uint32_t unk3[7];
> + uint32_t data;
> +} APMExtraData;
>
> -static void apm_parse_vs12(APMVS12Chunk *vs12, const uint8_t *buf)
> +static void apm_parse_extradata(APMExtraData *ed, const uint8_t *buf)
> {
> - vs12->magic = AV_RL32(buf + 0);
> - vs12->file_size = AV_RL32(buf + 4);
> - vs12->data_size = AV_RL32(buf + 8);
> - vs12->unk1 = AV_RL32(buf + 12);
> - vs12->unk2 = AV_RL32(buf + 16);
> -
> - vs12->state.has_saved = AV_RL32(buf + 20);
> - vs12->state.predictor_r = AV_RL32(buf + 24);
> - vs12->state.step_index_r = AV_RL32(buf + 28);
> - vs12->state.saved_r = AV_RL32(buf + 32);
> - vs12->state.predictor_l = AV_RL32(buf + 36);
> - vs12->state.step_index_l = AV_RL32(buf + 40);
> - vs12->state.saved_l = AV_RL32(buf + 44);
> -
> - for (int i = 0; i < FF_ARRAY_ELEMS(vs12->pad); i++)
> - vs12->pad[i] = AV_RL32(buf + 48 + (i * 4));
> + ed->magic = AV_RL32(buf + 0);
> + ed->file_size = AV_RL32(buf + 4);
> + ed->data_size = AV_RL32(buf + 8);
> + ed->unk1 = AV_RL32(buf + 12);
> + ed->unk2 = AV_RL32(buf + 16);
> +
> + ed->state.has_saved = AV_RL32(buf + 20);
> + ed->state.predictor_r = AV_RL32(buf + 24);
> + ed->state.step_index_r = AV_RL32(buf + 28);
> + ed->state.saved_r = AV_RL32(buf + 32);
> + ed->state.predictor_l = AV_RL32(buf + 36);
> + ed->state.step_index_l = AV_RL32(buf + 40);
> + ed->state.saved_l = AV_RL32(buf + 44);
> +
> + for (int i = 0; i < FF_ARRAY_ELEMS(ed->unk3); i++)
> + ed->unk3[i] = AV_RL32(buf + 48 + (i * 4));
> +
> + ed->data = AV_RL32(buf + 76);
> }
>
> static int apm_probe(const AVProbeData *p)
> @@ -94,71 +98,75 @@ static int apm_read_header(AVFormatContext *s)
> {
> int64_t ret;
> AVStream *st;
> - APMVS12Chunk vs12;
> - uint8_t buf[APM_VS12_CHUNK_SIZE];
> + APMExtraData extradata;
> + AVCodecParameters *par;
> + uint8_t buf[APM_FILE_EXTRADATA_SIZE];
>
> if (!(st = avformat_new_stream(s, NULL)))
> return AVERROR(ENOMEM);
>
> - /* The header starts with a WAVEFORMATEX */
> - if ((ret = ff_get_wav_header(s, s->pb, st->codecpar, APM_FILE_HEADER_SIZE, 0)) < 0)
> - return ret;
> -
> - if (st->codecpar->bits_per_coded_sample != 4)
> + /*
> + * This is 98% a WAVEFORMATEX, but there's something screwy with the extradata
> + * that ff_get_wav_header() can't (and shouldn't) handle properly.
> + */
> + if (avio_rl16(s->pb) != APM_TAG_CODEC)
> return AVERROR_INVALIDDATA;
>
> - if (st->codecpar->codec_tag != APM_TAG_CODEC)
> + par = st->codecpar;
> + par->channels = avio_rl16(s->pb);
> + par->sample_rate = avio_rl32(s->pb);
> + par->bit_rate = avio_rl32(s->pb) * 8;
> + par->block_align = avio_rl16(s->pb);
> + par->bits_per_coded_sample = avio_rl16(s->pb);
> +
> + if (avio_rl16(s->pb) != APM_FILE_EXTRADATA_SIZE)
> return AVERROR_INVALIDDATA;
>
> - /* ff_get_wav_header() does most of the work, but we need to fix a few things. */
> - st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_APM;
> - st->codecpar->codec_tag = 0;
> + if (par->bits_per_coded_sample != 4)
> + return AVERROR_INVALIDDATA;
>
> - if (st->codecpar->channels == 2)
> - st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
> - else if (st->codecpar->channels == 1)
> - st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
> + if (par->channels == 2)
> + par->channel_layout = AV_CH_LAYOUT_STEREO;
> + else if (par->channels == 1)
> + par->channel_layout = AV_CH_LAYOUT_MONO;
> else
> return AVERROR_INVALIDDATA;
>
> - st->codecpar->format = AV_SAMPLE_FMT_S16;
> - st->codecpar->bits_per_raw_sample = 16;
> - st->codecpar->bit_rate = st->codecpar->channels *
> - st->codecpar->sample_rate *
> - st->codecpar->bits_per_coded_sample;
> + par->codec_type = AVMEDIA_TYPE_AUDIO;
> + par->codec_id = AV_CODEC_ID_ADPCM_IMA_APM;
> + par->format = AV_SAMPLE_FMT_S16;
> + par->bits_per_raw_sample = 16;
> +
> + /* Now skip the pad that ruins everything. */
> + if ((ret = avio_skip(s->pb, 2)) < 0)
> + return ret;
>
> - if ((ret = avio_read(s->pb, buf, APM_VS12_CHUNK_SIZE)) < 0)
> + if ((ret = avio_read(s->pb, buf, APM_FILE_EXTRADATA_SIZE)) < 0)
> return ret;
> - else if (ret != APM_VS12_CHUNK_SIZE)
> + else if (ret != APM_FILE_EXTRADATA_SIZE)
> return AVERROR(EIO);
>
> - apm_parse_vs12(&vs12, buf);
> + apm_parse_extradata(&extradata, buf);
>
> - if (vs12.magic != APM_TAG_VS12) {
> + if (extradata.magic != APM_TAG_VS12 || extradata.data != APM_TAG_DATA)
> return AVERROR_INVALIDDATA;
> - }
>
> - if (vs12.state.has_saved) {
> + if (extradata.state.has_saved) {
> avpriv_request_sample(s, "Saved Samples");
> return AVERROR_PATCHWELCOME;
> }
>
> - if (avio_rl32(s->pb) != APM_TAG_DATA)
> - return AVERROR_INVALIDDATA;
> -
> - if ((ret = ff_alloc_extradata(st->codecpar, 16)) < 0)
> + if ((ret = ff_alloc_extradata(par, APM_EXTRADATA_SIZE)) < 0)
> return ret;
>
> - AV_WL32(st->codecpar->extradata + 0, vs12.state.predictor_l);
> - AV_WL32(st->codecpar->extradata + 4, vs12.state.step_index_l);
> - AV_WL32(st->codecpar->extradata + 8, vs12.state.predictor_r);
> - AV_WL32(st->codecpar->extradata + 12, vs12.state.step_index_r);
> + /* Use the entire state as extradata. */
> + memcpy(par->extradata, buf + 20, APM_EXTRADATA_SIZE);
>
> - avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
> + avpriv_set_pts_info(st, 64, 1, par->sample_rate);
> st->start_time = 0;
> - st->duration = vs12.data_size *
> - (8 / st->codecpar->bits_per_coded_sample) /
> - st->codecpar->channels;
> + st->duration = extradata.data_size *
> + (8 / par->bits_per_coded_sample) /
> + par->channels;
> return 0;
> }
>
>
So in this and the next patch you change the format of the extradata.
This patch here breaks fate (every patch of a patchset is supposed to
pass fate, not only the last one) which is unacceptable. But there is a
more serious problem: Updating the extradata stuff affects more than one
library, namely libavcodec and libavformat. And it is allowed to update
libavcodec alone (as long as the major version doesn't change) without
updating libavformat. So one could come into a situation where one uses
a libavformat exporting the old extradata format and libavcodec only
accepting the new one. A solution for this would be to accept both
formats in libavcodec (they can easily be distinguished by the extradata
size). The patch for libavcodec would have to go in first. That way fate
wouldn't need any update.
Furthermore, why are you parsing (i.e. copying around) the unk1-3 (I
guess it means "unknown"?) when you don't use it at all? And given that
you now simply use the extradata as it has been read, it might be better
to use ff_get_extradata directly.
- Andreas
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